News Topic emotion
About these topic collections
I’ve been reporting on memory research for over ten years and these topic pages are simply collections of all the news items I have made on a particular topic. They do not pretend to be in any way exhaustive! I cover far too many areas within memory to come anywhere approaching that. What I aim to do is provide breadth, rather than depth. Outside my own area of cognitive psychology, it is difficult to know how much weight to give to any study (I urge you to read my blog post on what constitutes scientific evidence). That (among other reasons) is why my approach in my news reporting is based predominantly on replication and consistency. It's about the aggregate. So here is the aggregate of those reports I have at one point considered of sufficient interest to discuss. If you know of any research you would like to add to the collection, feel free to write about it in a comment (please provide a reference).
By using brain scans from 152 Vietnam veterans with a variety of combat-related brain injuries, researchers claim to have mapped the neural basis of general intelligence and emotional intelligence.
There was significant overlap between general intelligence and emotional intelligence, both in behavioral measures and brain activity. Higher scores on general intelligence tests and personality reliably predicted higher performance on measures of emotional intelligence, and many of the same brain regions (in the frontal and parietal cortices) were found to be important to both.
More specifically, impairments in emotional intelligence were associated with selective damage to a network containing the extrastriate body area (involved in perceiving the form of other human bodies), the left posterior superior temporal sulcus (helps interpret body movement in terms of intentions), left temporo-parietal junction (helps work out other person’s mental state), and left orbitofrontal cortex (supports emotional empathy). A number of associated major white matter tracts were also part of the network.
Two of the components of general intelligence were strong contributors to emotional intelligence: verbal comprehension/crystallized intelligence, and processing speed. Verbal impairment was unsurprisingly associated with selective damage to the language network, which showed some overlap with the network underlying emotional intelligence. Similarly, damage to the fronto-parietal network linked to deficits in processing speed also overlapped in places with the emotional intelligence network.
Only one of the ‘big five’ personality traits contributed to the prediction of emotional intelligence — conscientiousness. Impairments in conscientiousness were associated with damage to brain regions widely implicated in social information processing, of which two areas (left orbitofrontal cortex and left temporo-parietal junction) were also involved in impaired emotional intelligence, suggesting where these two attributes might be connected (ability to predict and understand another’s emotions).
It’s interesting (and consistent with the growing emphasis on connectivity rather than the more simplistic focus on specific regions) that emotional intelligence was so affected by damage to white matter tracts. The central role of the orbitofrontal cortex is also intriguing – there’s been growing evidence in recent years of the importance of this region in emotional and social processing, and it’s worth noting that it’s in the right place to integrate sensory and bodily sensation information and pass that onto decision-making systems.
All of this is to say that emotional intelligence depends on social information processing and general intelligence. Traditionally, general intelligence has been thought to be distinct from social and emotional intelligence. But humans are fundamentally social animals, and – contra the message of the Enlightenment, that we have taken so much to heart – it has become increasingly clear that emotions and reason are inextricably entwined. It is not, therefore, all that surprising that general and emotional intelligence might be interdependent. It is more surprising that conscientiousness might be rooted in your degree of social empathy.
It’s also worth noting that ‘emotional intelligence’ is not simply a trendy concept – a pop quiz question regarding whether you ‘have a high EQ’ (or not), but that it can, if impaired, produce very real problems in everyday life.
Emotional intelligence was measured by the Mayer, Salovey, Caruso Emotional Intelligence Test (MSCEIT), general IQ by the Wechsler Adult Intelligence Scale, and personality by the Neuroticism-Extroversion-Openness Inventory.
 Distributed neural system for emotional intelligence revealed by lesion mapping. Social Cognitive and Affective Neuroscience.(2012).
I’ve spoken before about the effects of motivation on test performance. This is displayed in a fascinating study by researchers at the Educational Testing Service, who gave one of their widely-used tests (the ETS Proficiency Profile, short form, plus essay) to 757 students from three institutions: a research university, a master's institution and a community college. Here’s the good bit: students were randomly assigned to groups, each given a different consent form. In the control condition, students were told: “Your answers on the tests and the survey will be used only for research purposes and will not be disclosed to anyone except the research team.” In the “Institutional” condition, the rider was added: “However, your test scores will be averaged with all other students taking the test at your college.” While in the “Personal” condition, they were told instead: “However, your test scores may be released to faculty in your college or to potential employers to evaluate your academic ability.”
No prizes for guessing which of these was more motivating!
Students in the “personal” group performed significantly and consistently better than those in the control group at all three institutions. On the multi-choice part of the test, the personal group performed on average .41 of the standard deviation higher than the control group, and the institutional group performed on average .26 SD higher than the controls. The largest difference was .68 SD. On the essay, the largest effect size was .59 SD. (The reason for the results being reported this way is because the focus of the study was on the use of such tests to assess and compare learning gains by colleges.)
The effect is perhaps less dramatic at the individual level, with the average sophomore score on the multichoice test being 460, compared to 458 and 455, for personal, institutional, and control groups, respectively. Interestingly, this effect was greater at the senior level: 469 vs 466 vs 460. For the essay question, however, the effect was larger: 4.55 vs 4.35 vs 4.21 (sophomore); 4.75 vs 4.37 vs 4.37 (senior). (Note that these scores have been adjusted by college admission scores).
Students also reported on motivation level, and this was found to be a significant predictor of test performance, after controlling for SAT or placement scores.
Student participants had received at least one year of college, or (for community colleges) taken at least three courses.
The findings confirm recently expressed concern that students don’t put their best efforts into low-stakes tests, and that, when such tests are used to make judgments about institutional performance (how much value they add), they may well be significantly misleading, if different institutions are providing different levels of motivation.
On a personal level, of course, the findings may be taken as further confirmation of the importance of non-academic factors in academic achievement. Something looked at more directly in the next study.
Motivation, study habits—not IQ—determine growth in math achievement
Data from a large German longitudinal study assessing math ability in adolescents found that, although intelligence was strongly linked to students' math achievement, this was only in the initial development of competence. The significant predictors of growth in math achievement, however, were motivation and study skills.
Specifically (and excitingly for me, since it supports some of my recurring themes!), at the end of Grade 5, perceived control was a significant positive predictor for growth, and surface learning strategies were a significant negative predictor. ‘Perceived control’ reflects the student’s belief that their grades are under their control, that their efforts matter. ‘Surface learning strategies’ reflect the use of rote memorization/rehearsal strategies rather than ones that encourage understanding. (This is not to say, of course, that these strategies don’t have their place — but they need to be used appropriately).
At the end of Grade 7, however, a slightly different pattern emerged, with intrinsic motivation and deep learning strategies the significant positive predictors of growth, while perceived control and surface learning strategies were no longer significant.
In other words, while intelligence didn’t predict growth at either point, the particular motivational and strategy variables that affected growth were different at different points in time, reflecting, presumably, developmental changes and/or changes in academic demands.
Note that this is not to say that intelligence doesn’t affect math achievement! It is, indeed, a strong predictor — but through its effect on getting the student off to a good start (lifting the starting point) rather than having an ongoing benefit.
There was, sadly but unfortunately consistent with other research, an overall decline in motivation from grade 5 to 7. There was also a smaller decline in strategy use (any strategy! — presumably reflecting the declining motivation).
It’s also worth noting that (also sadly but unsurprisingly) the difference between school types increased over time, with those in the higher track schools making more progress than those in the lowest track.
The last point I want to emphasize is that extrinsic motivation only affected initial levels, not growth. The idea that extrinsic motivation (e.g., wanting good grades) is of only short-term benefit, while intrinsic motivation (e.g., being interested in the subject) is far more durable, is one I have made before, and one that all parents and teachers should pay attention to.
The study involved 3,520 students, following them from grades 5 to 10. The math achievement test was given at the end of each grade, while intelligence and self-reported motivation and strategy use were assessed at the end of grades 5 and 7. Intelligence was assessed using the nonverbal reasoning subtest of Thorndike’s Cognitive Abilities Test (German version). The 42 schools in the study were spread among the three school types: lower-track (Hauptschule), intermediate-track (Realschule), and higher-track (Gymnasium). These school types differ in entrance standards and academic demands.
 Measuring Learning Outcomes in Higher Education Motivation Matters. Educational Researcher. 41(9), 352 - 362.(2012).
 Predicting Long-Term Growth in Students' Mathematics Achievement: The Unique Contributions of Motivation and Cognitive Strategies. Child Development. n/a - n/a.(2012).
More evidence that even an 8-week meditation training program can have measurable effects on the brain comes from an imaging study. Moreover, the type of meditation makes a difference to how the brain changes.
The study involved 36 participants from three different 8-week courses: mindful meditation, compassion meditation, and health education (control group). The courses involved only two hours class time each week, with meditation students encouraged to meditate for an average 20 minutes a day outside class. There was a great deal of individual variability in the total amount of meditation done by the end of the course (210-1491 minutes for the mindful attention training course; 190-905 minutes for the compassion training course).
Participants’ brains were scanned three weeks before the courses began, and three weeks after the end. During each brain scan, the volunteers viewed 108 images of people in situations that were either emotionally positive, negative or neutral.
In the mindful attention group, the second brain scan showed a decrease in activation in the right amygdala in response to all images, supporting the idea that meditation can improve emotional stability and response to stress. In the compassion meditation group, right amygdala activity also decreased in response to positive or neutral images, but, among those who reported practicing compassion meditation most frequently, right amygdala activity tended to increase in response to negative images. No significant changes were seen in the control group or in the left amygdala of any participant.
The findings support the idea that meditation can be effective in improving emotional control, and that compassion meditation can indeed increase compassionate feelings. Increased amygdala activation was also correlated with decreased depression scores in the compassion meditation group, which suggests that having more compassion towards others may also be beneficial for oneself.
The findings also support the idea that the changes brought about by meditation endure beyond the meditative state, and that the changes can start to occur quite quickly.
These findings are all consistent with other recent research.
One point is worth emphasizing, in the light of the difficulty in developing a training program that improves working memory rather than simply improving the task being practiced. These findings suggest that, unlike most cognitive training programs, meditation training might produce learning that is process-specific rather than stimulus- or task-specific, giving it perhaps a wider generality than most cognitive training.
 Effects of mindful-attention and compassion meditation training on amygdala response to emotional stimuli in an ordinary, non-meditative state. Frontiers in Human Neuroscience. 6,(2012).
Full text available at http://www.frontiersin.org/human_neuroscience/10.3389/fnhum.2012.00292/a...
The neurotransmitter dopamine is found throughout the brain and has been implicated in a number of cognitive processes, including memory. It is well-known, of course, that Parkinson's disease is characterized by low levels of dopamine, and is treated by raising dopamine levels.
A new study of older adults has now demonstrated the effect of dopamine on episodic memory. In the study, participants (aged 65-75) were shown black and white photos of indoor scenes and landscapes. The subsequent recognition test presented them with these photos mixed in with new ones, and required them to note which photos they had seen before. Half of the participants were first given Levodopa (‘L-dopa’), and half a placebo.
Recognition tests were given two and six hours after being shown the photos. There was no difference between the groups at the two-hour test, but at the six-hour test, those given L-dopa recognized up to 20% more photos than controls.
The failure to find a difference at the two-hour test was expected, if dopamine’s role is to help strengthen the memory code for long-term storage, which occurs after 4-6 hours.
Individual differences indicated that the ratio between the amount of Levodopa taken and body weight is key for an optimally effective dose.
The findings therefore suggest that at least part of the reason for the decline in episodic memory typically seen in older adults is caused by declining levels of dopamine.
Given that episodic memory is one of the first and greatest types of memory hit by Alzheimer’s, this finding also has implications for Alzheimer’s treatment.
Caffeine improves recognition of positive words
Another recent study also demonstrates, rather more obliquely, the benefits of dopamine. In this study, 200 mg of caffeine (equivalent to 2-3 cups of coffee), taken 30 minutes earlier by healthy young adults, was found to improve recognition of positive words, but had no effect on the processing of emotionally neutral or negative words. Positive words are consistently processed faster and more accurately than negative and neutral words.
Because caffeine is linked to an increase in dopamine transmission (an indirect effect, stemming from caffeine’s inhibitory effect on adenosine receptors), the researchers suggest that this effect of caffeine on positive words demonstrates that the processing advantage enjoyed by positive words is driven by the involvement of the dopaminergic system.
 Dopamine Modulates Episodic Memory Persistence in Old Age. The Journal of Neuroscience. 32(41), 14193 - 14204.(2012).
 Caffeine Improves Left Hemisphere Processing of Positive Words. PLoS ONE. 7(11),(2012).
Full text available at http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0048487
We know that emotion affects memory. We know that attention affects perception (see, e.g., Visual perception heightened by meditation training; How mindset can improve vision). Now a new study ties it all together. The study shows that emotionally arousing experiences affect how well we see them, and this in turn affects how vividly we later recall them.
The study used images of positively and negatively arousing scenes and neutral scenes, which were overlaid with varying amounts of “visual noise” (like the ‘snow’ we used to see on old televisions). College students were asked to rate the amount of noise on each picture, relative to a specific image they used as a standard. There were 25 pictures in each category, and three levels of noise (less than standard, equal to standard, and more than standard).
Different groups explored different parameters: color; gray-scale; less noise (10%, 15%, 20% as compared to 35%, 45%, 55%); single exposure (each picture was only presented once, at one of the noise levels).
Regardless of the actual amount of noise, emotionally arousing pictures were consistently rated as significantly less noisy than neutral pictures, indicating that people were seeing them more clearly. This was true in all conditions.
Eye-tracking analysis ruled out the idea that people directed their attention differently for emotionally arousing images, but did show that more eye fixations were associated both with less noisy images and emotionally arousing ones. In other words, people were viewing emotionally important images as if they were less noisy.
One group of 22 students were given a 45-minute spatial working memory task after seeing the images, and then asked to write down all the details they could remember about the pictures they remembered seeing. The amount of detail they recalled was taken to be an indirect measure of vividness.
A second group of 27 students were called back after a week for a recognition test. They were shown 36 new images mixed in with the original 75 images, and asked to rate them as new, familiar, or recollected. They were also asked to rate the vividness of their recollection.
Although, overall, emotionally arousing pictures were not more likely to be remembered than neutral pictures, both experiments found that pictures originally seen as more vivid (less noise) were remembered more vividly and in more detail.
Brain scans from 31 students revealed that the amygdala was more active when looking at images rated as vivid, and this in turn increased activity in the visual cortex and in the posterior insula (which integrates sensations from the body). This suggests that the increased perceptual vividness is not simply a visual phenomenon, but part of a wider sensory activation.
There was another neural response to perceptual vividness: activity in the dorsolateral prefrontal cortex and the posterior parietal cortex was negatively correlated with vividness. This suggests that emotion is not simply increasing our attentional focus, it is instead changing it by reducing effortful attentional and executive processes in favor of more perceptual ones. This, perhaps, gives emotional memories their different ‘flavor’ compared to more neutral memories.
These findings clearly need more exploration before we know exactly what they mean, but the main finding from the study is that the vividness with which we recall some emotional experiences is rooted in the vividness with which we originally perceived it.
The study highlights how emotion can sharpen our attention, building on previous findings that emotional events are more easily detected when visibility is difficult, or attentional demands are high. It is also not inconsistent with a study I reported on last year, which found some information needs no repetition to be remembered because the amygdala decrees it of importance.
I should add, however, that the perceptual effect is not the whole story — the current study found that, although perceptual vividness is part of the reason for memories that are vividly remembered, emotional importance makes its own, independent, contribution. This contribution may occur after the event.
It’s suggested that individual differences in these reactions to emotionally enhanced vividness may underlie an individual’s vulnerability to post-traumatic stress disorder.
 Psychophysical and Neural Evidence for Emotion-Enhanced Perceptual Vividness. The Journal of Neuroscience. 32(33), 11201 - 11212.(2012).
Here’s an intriguing study for those interested in how language affects how we think. It’s also of interest to those who speak more than one language or are interested in learning another language, because it deals with the long-debated question as to whether bilinguals working in their non-native language automatically access the native-language representations in long-term memory, or whether they can ‘switch off’ their native language and use only the target language memory codes.
The study follows on from an earlier study by the same researchers that indicated, through the demonstration of hidden priming effects, that bilinguals subconsciously access their first language when reading in their second language. In this new study, 45 university students (15 native English speakers, 15 native Chinese speakers, and 15 Chinese-English bilinguals) were shown two blocks of 90 word pairs. The pairs could have positive emotional value (e.g., honesty-program), negative valence (failure-poet), or neutral valence (aim-carpenter); could be semantically related (virus-bacteria; love-rose) or unrelated (weather-gender). The English or Chinese words were flashed on the screen one at a time, with a brief interval between the first and second word. The students had to indicate whether the second word was related in meaning to the first, and their brain activity was monitored.
The English and Chinese speakers acted as controls — it was the bilinguals, of course, who were the real interest. Some of the English word pairs shared a sound in the Chinese translation. If the Chinese words were automatically activated, therefore, the sound repetition would have a priming effect.
This is indeed what was found (confirming the earlier finding and supporting the idea that native language translations are automatically activated) — but here’s the interesting thing: the priming effect occurred only for positive and neutral words. It did not occur when the bilinguals saw negative words such as war, discomfort, inconvenience, and unfortunate.
The finding, which surprised the researchers, is nonetheless consistent with previous evidence that anger, swearing or discussing intimate feelings has more power in a speaker's native language. Parents, too, tend to speak to their infants in their native tongue. Emotion, it seems, is more strongly linked to our first language.
It’s traditionally thought that second language processing is fundamentally determined by the age of acquisition and the level of proficiency. The differences in emotional resonance have been, naturally enough, attributed to the native language being acquired first. This finding suggests the story is a little more complicated.
The researchers theorize that they have touched on the mechanism by which emotion controls our fundamental thought processes. They suggest that the brain is trying to protect us by minimizing the effect of distressing or disturbing emotional content, by shutting down the unconscious access to the native language (in which the negative words would be more strongly felt).
A few more technical details for those interested:
The Chinese controls demonstrated longer reaction times than the English controls, which suggests (given that 60% of the Chinese word pairs had overt sound repetitions but no semantic relatedness) that this conjunction made the task substantially more difficult. The bilinguals, however, had reaction times comparable to the English controls. The Chinese controls showed no effect of emotional valence, but did show priming effects of the overt sound manipulation that were equal for all emotion conditions.
The native Chinese speakers had recently arrived in Britain to attend an English course. Bilinguals had been exposed to English since the age of 12 and had lived in Britain for an average of 20.5 months.
 How Reading in a Second Language Protects Your Heart. The Journal of Neuroscience. 32(19), 6485 - 6489.(2012).
Previous research has shown that negative objects and events are preferentially consolidated in sleep — if you experience them in the evening, you are more likely to remember them than more neutral objects or events, but if you experience them in the morning, they are not more likely to be remembered than other memories (see collected sleep reports). However, more recent studies have failed to find this. A new study also fails to find such preferential consolidation, but does find that our emotional reaction to traumatic or disturbing events can be greatly reduced if we stay awake afterward.
Being unable to sleep after such events is of course a common response — these findings indicate there’s good reason for it, and we should go along with it rather than fighting it.
The study involved 106 young adults rating pictures on a sad-happy scale and their own responses on an excited-calm scale. Twelve hours later, they were given a recognition test: noting pictures they had seen earlier from a mix of new and old pictures. They also rated all the pictures on the two scales. There were four groups: 41 participants saw the first set late in the day and the second set 12 hours later on the following day (‘sleep group’); 41 saw the first set early and the second set 12 hours later on the same day; 12 participants saw both sets in the evening, with only 45 minutes between the sets; 12 participants saw both sets in the morning (these last two groups were to rule out circadian effects). 25 of the sleep group had their brain activity monitored while they slept.
The sleep group performed significantly better on the recognition test than the same-day group. Negative pictures were remembered better than neutral ones. However, unlike earlier studies, the sleep group didn’t preferentially remember negative pictures more than the same-day group.
But, interestingly, the sleep group was more likely to maintain the strength of initial negative responses. The same-day group showed a weaker response to negative scenes on the second showing.
It’s been theorized that late-night REM sleep is critical for emotional memory consolidation. However, this study found no significant relationship between the amount of time spent in REM sleep and recognition memory, nor was there any relationship between other sleep stages and memory. There was one significant result: those who had more REM sleep in the third quarter of the night showed the least reduction of emotional response to the negative pictures.
There were no significant circadian effects, but it’s worth noting that even the 45 minute gap between the sets was sufficient to weaken the negative effect of negative scenes.
While there was a trend toward a gender effect, it didn’t reach statistical significance, and there were no significant interactions between gender and group or emotional value.
The findings suggest that the effects of sleep on memory and emotion may be independent.
The findings also contradict previous studies showing preferential consolidation of emotional memories during sleep, but are consistent with two other recent studies that have also failed to find this. At this stage, all we can say is that there may be certain conditions in which this occurs (or doesn’t occur), but more research is needed to determine what these conditions are. Bear in mind that there is no doubt that sleep helps consolidate memories; we are talking here only about emphasizing negative memories at the expense of emotionally-neutral ones.
 Processing of Emotional Reactivity and Emotional Memory over Sleep. The Journal of Neuroscience. 32(3), 1035 - 1042.(2012).
Certainly experiences that arouse emotions are remembered better than ones that have no emotional connection, but whether negative or positive memories are remembered best is a question that has produced equivocal results. While initial experiments suggested positive events were remembered better than negative, more recent studies have concluded the opposite.
The idea that negative events are remembered best is consistent with a theory that negative emotion signals a problem, leading to more detailed processing, while positive emotion relies more heavily on general scripts.
However, a new study challenges those recent studies, on the basis of a more realistic comparison. Rather than focusing on a single public event, to which some people have positive feelings while others have negative feelings (events used have included the OJ Simpson trial, the fall of the Berlin Wall, and a single baseball championship game), the study looked at two baseball championships each won by different teams.
The experiment involved 1,563 baseball fans who followed or attended the 2003 and 2004 American League Championship games between the New York Yankees (2003 winners) and the Boston Red Sox (2004 winners). Of the fans, 1,216 were Red Sox fans, 218 were Yankees fans, and 129 were neutral fans. (Unfortunately the selection process disproportionately collected Red Sox fans.)
Participants were reminded who won the championship before answering questions on each game. Six questions were identical for the two games: the final score for each team, the winning and losing pitchers (multiple choice of five pitchers for each team), the location of the game, and whether the game required extra innings. Participants also reported how vividly they remembered the game, and how frequently they had thought about or seen media concerning the game.
Both Yankee and Red Sox fans remembered more details about their team winning. They also reported more vivid memories for the games their team won. Accuracy and vividness were significantly correlated. Fans also reported greater rehearsal of the game their team won, and again, rehearsal and accuracy were significantly correlated.
Analysis of the data revealed that rehearsal completely mediated the correlation between accuracy and fan type, and partially mediated the correlation between vividness and fan type.
In other words, improved memory for emotion-arousing events has everything to do with how often you think about or are reminded of the event.
PTSD, for example, is the negative memory extreme. And PTSD is characterized by the unavoidable rehearsal of the event over and over again. Each repetition makes memory for the event stronger.
In the previous studies referred to earlier, media coverage provided a similarly unavoidable repetition.
While most people tend to recall more positive than negative events (and this tendency becomes greater with age), individuals who are depressed or anxious show the opposite tendency.
So whether positive or negative events are remembered better depends on you, as well as the event.
When it comes down to it, I'm not sure it's really a helpful question - whether positive or negative events are remembered better. An interesting aspect of public events is that their portrayal often changes over time, but this is just a more extreme example of what happens with private events as well — as we change over time, so does our attitude toward those events. Telling friends about events, and receiving their comments on them, can affect our emotional response to events, as well as having an effect on our memory of those events.
 Effects of Event Valence on Long-Term Memory for Two Baseball Championship Games. Psychological Science. 22(11), 1408 - 1412.(2011).
In a recent study, 40 undergraduate students learned ten lists of ten pairs of Swahili-English words, with tests after each set of ten. On these tests, each correct answer was followed by an image, either a neutral one or one designed to arouse negative emotions, or by a blank screen. They then did a one-minute multiplication test before moving on to the next section.
On the final test of all 100 Swahili-English pairs, participants did best on items that had been followed by the negative pictures.
In a follow-up experiment, students were shown the images two seconds after successful retrieval. The results were the same.
In the final experiment, the section tests were replaced by a restudying period, where each presentation of a pair was followed by an image or blank screen. The effect did not occur, demonstrating that the effect depends on retrieval.
The study focused on negative emotion because earlier research has found no such memory benefit for positive images (including images designed to be sexually arousing).
The findings emphasize the importance of the immediate period after retrieval, suggesting that this is a fruitful time for manipulations that enhance or impair memory. This is consistent with the idea of reconsolidation — that when information is retrieved from memory, it is in a labile state, able to be changed. Thus, by presenting a negative image when the retrieved memory is still in that state, the memory absorbs some of that new context.
 Enhancing Retention Through Reconsolidation. Psychological Science. 22(6), 781 - 786.(2011).
Once upon a time we made a clear difference between emotion and reason. Now increasing evidence points to the necessity of emotion for good reasoning. It’s clear the two are deeply entangled.
Now a new study has found that those with a higher working memory capacity (associated with greater intelligence) are more likely to automatically apply effective emotional regulation strategies when the need arises.
The study follows on from previous research that found that people with a higher working memory capacity suppressed expressions of both negative and positive emotion better than people with lower WMC, and were also better at evaluating emotional stimuli in an unemotional manner, thereby experiencing less emotion in response to those stimuli.
In the new study, participants were given a test, then given either negative or no feedback. A subsequent test, in which participants were asked to rate their familiarity with a list of people and places (some of which were fake), evaluated whether their emotional reaction to the feedback affected their performance.
This negative feedback was quite personal. For example: "your responses indicate that you have a tendency to be egotistical, placing your own needs ahead of the interests of others"; "if you fail to mature emotionally or change your lifestyle, you may have difficulty maintaining these friendships and are likely to form insecure relations."
The false items in the test were there to check for "over claiming" — a reaction well known to make people feel better about themselves and control their reactions to criticism. Among those who received negative feedback, those with higher levels of WMC were found to over claim the most. The people who over claimed the most also reported, at the end of the study, the least negative emotions.
In other words, those with a high WMC were more likely to automatically use an emotion regulation strategy. Other emotional reappraisal strategies include controlling your facial expression or changing negative situations into positive ones. Strategies such as these are often more helpful than suppressing emotion.
Schmeichel, Brandon J.; Demaree, Heath A. 2010. Working memory capacity and spontaneous emotion regulation: High capacity predicts self-enhancement in response to negative feedback. Emotion, 10(5), 739-744.
Schmeichel, Brandon J.; Volokhov, Rachael N.; Demaree, Heath A. 2008. Working memory capacity and the self-regulation of emotional expression and experience. Journal of Personality and Social Psychology, 95(6), 1526-1540. doi: 10.1037/a0013345
The role of sleep in consolidating memory is now well-established, but recent research suggests that sleep also reorganizes memories, picking out the emotional details and reconfiguring the memories to help you produce new and creative ideas. In an experiment in which participants were shown scenes of negative or neutral objects at either 9am or 9pm and tested 12 hours later, those tested on the same day tended to forget the negative scenes entirely, while those who had a night’s sleep tended to remember the negative objects but not their neutral backgrounds.
Follow-up experiments showed the same selective consolidation of emotional elements to a lesser degree after a 90-minute daytime nap, and to a greater degree after a 24-hour or even several-month delay (as long as sleep directly followed encoding).
These findings suggest that processes that occur during sleep increase the likelihood that our emotional responses to experiences will become central to our memories of them. Moreover, additional nights of sleep may continue to modify the memory.
In a different approach, another recent study has found that when volunteers were taught new words in the evening, then tested immediately, before spending the night in the sleep lab and being retested in the morning, they could remember more words in the morning than they did immediately after learning them, and they could recognize them faster. In comparison, a control group who were trained in the morning and re-tested in the evening showed no such improvement on the second test.
Deep sleep (slow-wave sleep) rather than rapid eye movement (REM) sleep or light sleep appeared to be the important phase for strengthening the new memories. Moreover, those who experienced more sleep spindles overnight were more successful in connecting the new words to the rest of the words in their mental lexicon, suggesting that the new words were communicated from the hippocampus to the neocortex during sleep. Sleep spindles are brief but intense bursts of brain activity that reflect information transfer between the hippocampus and the neocortex.
The findings confirm the role of sleep in reorganizing new memories, and demonstrate the importance of spindle activity in the process.
Taken together, these studies point to sleep being more important to memory than has been thought. The past decade has seen a wealth of studies establishing the role of sleep in consolidating procedural (skill) memory, but these findings demonstrate a deeper, wider, and more ongoing process. The findings also emphasize the malleability of memory, and the extent to which they are constructed (not copied) and reconstructed.
 Sleep’s Role in the Consolidation of Emotional Episodic Memories. Current Directions in Psychological Science. 19(5), 290 - 295.(2010).
 Sleep Spindle Activity is Associated with the Integration of New Memories and Existing Knowledge. J. Neurosci.. 30(43), 14356 - 14360.(2010).
A study involving 120 toddlers, tested at 14, 24, and 36 months, has assessed language skills (spoken vocabulary and talkativeness) and the development of self-regulation. Self-regulation is an important skill that predicts later academic and social success. Previous research has found that language skills (and vocabulary in particular) help children regulate their emotions and behavior. Boys have also been shown to lag behind girls in both language and self-regulation.
The present study hoped to explain inconsistencies in previous research findings by accounting for general cognitive development and possible gender differences. It found that vocabulary was more important than talkativeness, and 24-month vocabulary predicted the development of self-regulation even when general cognitive development was accounted for. However, girls seemed ‘naturally’ better able to control themselves and focus, but the ability in boys was much more associated with language skills. Boys with a strong vocabulary showed a dramatic increase in self-regulation, becoming comparable to girls with a strong vocabulary.
These gender differences suggest that language skills may be more important for boys, and that more emphasis should be placed on encouraging young boys to use words to solve problems, rather than accepting that ‘boys will be boys’.
 Use your words: The role of language in the development of toddlers' self-regulation. Early Childhood Research Quarterly. In Press, Uncorrected Proof,(Submitted).
A number of studies in recent years have revealed the amazing ability of the human brain to compensate for damage down to its part. In the latest of these, it’s been found that loss of the amygdala doesn’t have to mean that new memories will be void of emotion. Instead, it appears, a region called the bed nuclei can step in to take its place. The bed nuclei are slower to process information than the amygdala, and in normal circumstances are inhibited by the amygdala. The study looked specifically at fear conditioning, for which the amygdala has been considered crucial.
The finding offers the hope that therapies to promote compensatory shifts in function might help those who have suffered damage to parts of their brain.
 Compensation in the neural circuitry of fear conditioning awakens learning circuits in the bed nuclei of the stria terminalis. Proceedings of the National Academy of Sciences. 107(33), 14881 - 14886.(2010).
A small study suggests that the apathy shown by many Alzheimer's patients may not simply be due to memory or language problems, but to a decreased ability to experience emotions. The seven patients were asked to rate pictures of positive and negative scenes (such as babies and spiders) by putting a mark closer or further to either a happy face or a sad face emoticon. Closeness to the face indicated the strength of the emotion felt. Although most of the time the Alzheimer’s patients placed their mark in the appropriate direction, they did make more inappropriate choices than the control group, and typically also gave less intense judgments.
Both comprehension problems and depression were ruled out. A lower emotional response may result from damage to brain areas that produce neurotransmitters, which typically occurs early in Alzheimer’s. It may be that medication to replace or increase these neurotransmitters would improve emotional experience.
This finding is a warning that apathy should not be automatically taken to mean that the patient is depressed. The researchers, enabled by the small size of the study, tested more thoroughly for depression than is usually the case in large studies. It may be that in these studies, this apathy has often been confounded with depression — which may explain the inconsistencies in the research into depression and Alzheimer’s (see the news item just previous to this).
The finding may also help caregivers understand that any emotional indifference is not ‘personal’.
 Emotional Indifference in Alzheimer's Disease. J Neuropsychiatry Clin Neurosci. 22(2), 236 - 242.(2010).
An imaging study reveals why older adults are better at remembering positive events. The study, involving young adults (ages 19-31) and older adults (ages 61-80) being shown a series of photographs with positive and negative themes, found that while there was no difference in brain activity patterns between the age groups for the negative photos, there were age differences for the positive photos. In older adult brains, but not the younger, two emotion-processing regions (the ventromedial prefrontal cortex and the amygdala) strongly influenced the memory-encoding hippocampus.
 There are age-related changes in neural connectivity during the encoding of positive, but not negative, information. Cortex. 46(4), 425 - 433.(2010).
A study involving five patients with severe amnesia due to damage in the hippocampus, resulting in a condition comparable to Alzheimer's, has found that memory tests given 5-10 minutes after sad and happy film clips showed little (if any) memory of the details, but the generated emotion lasted for 20 to 30 minutes afterward. Interestingly, normal controls also felt happy for about the same length of time, but the impact of sad scenes was shorter. The findings challenge the idea that by minimizing a specific memory of past trauma, associated sadness will also decrease. Indeed, it may be that forgetting the details of unhappy events prolongs the effects. The findings also point to the need for care in dealing with those with impaired memory — don’t assume that any induced emotion will vanish as quickly as their memory of it.
 Sustained experience of emotion after loss of memory in patients with amnesia. Proceedings of the National Academy of Sciences. 107(17), 7674 - 7679.(2010).
Older news items (pre-2010) brought over from the old website
- How emotion affects memory (general)
- Motivation & attitude
- Stress & anxiety
- Fear & trauma
- Gender & age effects
- Gender & race stereotypes
Mixed feelings not remembered as well as happy or sad ones
A series of studies that tested participants' emotions when they faced scenarios such as taking tests and moving, events that are typically associated with mixed emotions, has found that the intensity of mixed emotions tends to be underestimated when recalling the experience. This underestimation increases over time, to the point that people sometimes don't remember having felt ambivalent at all. This is more likely among those who are uncomfortable feeling mixed emotions. Interestingly, Asian Americans in the study did not exhibit the same degree of memory decline for mixed emotions as Anglo-Americans did.
Aaker, J., Drolet, A. & Griffin, D. 2008. Recalling Mixed Emotions. Journal of Consumer Research, 35 (2), 268-278.
Emotions help memory, at the cost of other memories
Do we remember emotionally charged events better? Maybe — but at a price. A new study presented volunteers with lists of neutral words with one disturbing noun, such as murder or scream, embedded. As expected, the emotional words were much better remembered than the neutral words. More interestingly, the poorest memory occurred for neutral words that were presented immediately before the disturbing words. The effect was greater for women — women forgot those words twice as often as men.
 An emotion-induced retrograde amnesia in humans is amygdala- and beta-adrenergic-dependent. Proceedings of the National Academy of Sciences of the United States of America. 100(23), 13626 - 13631.(2003).
How memory helps make life pleasant
Surveys consistently show that people are generally happy with their lives. A review of research into autobiographical memory suggests why - human memory is biased toward happiness. Across 12 studies conducted by five different research teams, people of different racial and ethnic backgrounds and of different ages consistently reported experiencing more positive events in their lives than negative events, suggesting that pleasant events do in fact outnumber unpleasant events because people seek out positive experiences and avoid negative ones. Our memory also treats pleasant emotions differently from unpleasant emotions. Pleasant emotions appear to fade more slowly from our memory than unpleasant emotions. This is not repression; people do remember negative events, they just remember them less negatively. Among those with mild depression, however, unpleasant and pleasant emotions tend to fade evenly.
Walker, W.R., Skowronski, J.J. & Thompson, C.P. 2003. Life Is Pleasant -- and Memory Helps to Keep It That Way! Review of General Psychology, 7(2),203-10.
Suppressing your expression of emotion affects your memory for the event
The way people go about controlling their reactions to emotional events affects their memory of the event. In a series of experiments designed to assess the effect of suppressing the expression of emotion, it was found that, when people were shown a video of an emotional event and instructed not to let their emotions show, they had poorer memory for what was said and done than did those people who were given no such instructions. However, when shown slides of people who had been injured, people in both groups were equally good at picking which in an array of subtly different versions of each slide had been shown earlier - but when prompted to recall information that had been presented verbally with each slide, those in the suppression group again remembered fewer details. People who were asked to adopt the neutral attitude of a medical profession however, performed better than the control group on nonverbal recall, indicating the regulation of emotions via reappraisal was not associated with any memory impairment. These experimental results were supported by a naturalistic study.
 Emotion regulation and memory: The cognitive costs of keeping one's cool.. Journal of Personality and Social Psychology. 79(3), 410 - 424.(2000).
When mood affects memory
The effect of mood on memory depends on what questions are asked; only some aspects of memory are affected by incidental mood. For example, your memory of a restaurant's food won't be affected by the mood you were in when you ate it, but your memory of how much you enjoyed it will be. A new study shows that the effects of mood also depend on whether you had thought about that aspect during the experience — whether you had thought about how enjoyable the experience was at the time. In the study, people were shown a painting. Half of them were first put in a negative mood by reading and answering questions about an unpleasant subject. After looking at the painting, half were asked what they thought of it. Five days later, the participants were all asked how much they had liked the painting. While being in a negative mood had affected those who had evaluated the painting at the time, it did not affect those who had not made an evaluation at the time of presentation.
Pocheptsova, A. & Novemsky, N. 2009. When Do Incidental Mood Effects Last? Lay Beliefs versus Actual Effects. Journal of Consumer Research, Published online September 10, 2009
Perception affected by mood
An imaging study has revealed that when people were shown a composite image with a face surrounded by "place" images, such as a house, and asked to identify the gender of the face, those in whom a bad mood had been induced didn’t process the places in the background. However, those in a good mood took in both the focal and background images. These differences in perception were coupled with differences in activity in the parahippocampal place area. Increasing the amount of information is of course not necessarily a good thing, as it may result in more distraction.
 Opposing Influences of Affective State Valence on Visual Cortical Encoding. J. Neurosci.. 29(22), 7199 - 7207.(2009).
Positive mood may not help in tasks requiring attention to detail
A series of experiments with different child age groups who had happy or sad moods induced with the aid of music and selected video clips before then being asked to undertake a task that required attention to detail has found that the children induced to feel a sad or neutral mood performed the task better than those induced to feel happy. Other research has found that a positive mood is beneficial in other situations, such as when a task calls for creative thinking.
 A hidden cost of happiness in children. Developmental Science. 11, F25-F30 - F25-F30.(2008).
A study of 55 healthy adults has found that those who had high levels of long-chain omega-3 fatty acids had more gray matter in areas of the brain associated with emotional arousal and regulation — the bilateral anterior cingulate cortex, the right amygdala and the right hippocampus. Although this doesn’t mean omega-3 necessarily causes such changes, the finding does support a recent study that found higher levels of omega-3 were associated with a more positive outlook, and animal studies showing that increasing omega-3 intake leads to structural changes in the brain. Good sources of omega-3 fatty acids are walnuts, flax, and fatty fish such as salmon and sardines.
The findings were presented March 7 at the American Psychosomatic Society's Annual Meeting, in Budapest, Hungary.
Insight into the processes of 'positive' and 'negative' learners
An intriguing study of the electrical signals emanating from the brain has revealed two types of learners. A brainwave event called an "event-related potential" (ERP) is important in learning; a particular type of ERP called "error-related negativity" (ERN), is associated with activity in the anterior cingulate cortex. This region is activated during demanding cognitive tasks, and ERNs are typically more negative after participants make incorrect responses compared to correct choices. Unexpectedly, studies of this ERN found a difference between "positive" learners, who perform better at choosing the correct response than avoiding the wrong one, and "negative" learners, who learn better to avoid incorrect responses. The negative learners showed larger ERNs, suggesting that "these individuals are more affected by, and therefore learn more from, their errors.” Positive learners had larger ERNs when faced with high-conflict win/win decisions among two good options than during lose/lose decisions among two bad options, whereas negative learners showed the opposite pattern.
 Error-Related Negativity Predicts Reinforcement Learning and Conflict Biases. Neuron. 47(4), 495 - 501.(2005).
Positive emotions help people see big picture details
A study involving 89 students, who watched a video designed to induce either joy and laughter, anxiety, or no emotion, found that those who were in a positive mood had a far greater ability to recognize members of another race when briefly shown photos of individuals. In the absence of positive emotions, subjects recognized members of their own race 75% of the time but only recognized members of another race 65% of the time. Their ability to recognize members of their own race was unaffected by their emotional state.
 “We All Look the Same to Me”. Psychological Science. 16(11), 875 - 881.(2005).
Mood affects eyewitness accuracy and reasoning
A new study suggests people in a negative mood provide more accurate eyewitness accounts than people in a positive mood state. Moreover, people in a positive mood showed poorer judgment and critical thinking skills than those in a negative mood. The researchers suggest that a negative mood state triggers more systematic and attentive, information processing, while good moods signal a benign, non-threatening environment where we don't need to be so vigilant.
 Mood effects on eyewitness memory: Affective influences on susceptibility to misinformation. Journal of Experimental Social Psychology. 41(6), 574 - 588.(2005).
Excitement helps memory for unrelated events
We’ve long known that emotionally charged events are easier to remember than boring ones. New research suggests that the reason is the flood of emotion, not the personal meaningfulness of the event. Subjects asked to memorize a list of words did better if they subsequently watched a gory film of a bloody dental extraction, rather than a dull video on tooth brushing.
Nielson, K.A., Yee, D. & Erickson, K.I. 2002. Modulation of memory storage processes by post-training emotional arousal from a semantically unrelated source. Paper presented at the Society for Neuroscience annual meeting in Orlando, Florida, 4 November.
Mood needs to be matched to cognitive task for best performance
An imaging study looked at the brain activity of 14 college-aged men and women as they performed difficult cognitive tasks requiring the active retention of information in working memory, after watching short, emotional videos, designed to elicit one of three emotional states: pleasant, neutral or anxious. It was found that mild anxiety improved performance on some tasks, but hurt performance on others. Being in a pleasant mood boosted some kinds of performance but impaired other kinds. A region of the prefrontal cortex was jointly influenced by a combination of mood state and cognitive task, but not by either one alone.
 Integration of emotion and cognition in the lateral prefrontal cortex. Proceedings of the National Academy of Sciences of the United States of America. 99(6), 4115 - 4120.(2002).
Brain study shows how surprises help us learn
Because they are hard to forget, surprises can help us learn. Now scientists have identified a part of the brain that may be involved in learning from surprises. A team led by Dr. Paul C. Fletcher at the University of Cambridge monitored the brain activity in a group of volunteers who were participating in a simulation exercise. The participants pretended to work at drug companies and were asked to predict whether a particular fictitious drug would trigger a particular fictitious syndrome. In the early phase of the study, when the participants were not familiar with the effects of the various drugs, imaging tests detected high levels of activity in this part of the brain. As the volunteers became familiar with the effects of the drugs, so that they were no longer surprised by the results, activity in the dorsolateral prefrontal cortex declined, but later in the study, this region became more active when the participants were surprised by unexpected responses.
 Responses of human frontal cortex to surprising events are predicted by formal associative learning theory. Nat Neurosci. 4(10), 1043 - 1048.(2001).
Confidence as important as IQ in exam success
I’ve talked repeatedly about the effects of self-belief on memory and cognition. One important area in which this is true is that of academic achievement. Evidence indicates that your perceived abilities matter, just as much? more than? your actual abilities. It has been assumed that self perceived abilities, self-confidence if you will, is a product mainly of nurture. Now a new twin study provides evidence that nurture / environment may only provide half the story; the other half may lie in the genes. The study involved 1966 pairs of identical twins and 1877 pairs of fraternal twins. The next step is to tease out which of these genes are related to IQ and which to personality variables.
 More Than Just IQ: School Achievement Is Predicted by Self-Perceived Abilities—But for Genetic Rather Than Environmental Reasons. Psychological Science. 20(6), 753 - 762.(2009).
Anticipation strengthens memory
An imaging study has revealed that the amygdala and the hippocampus become activated when a person is anticipating a difficult situation (some type of gruesome picture). Moreover, the higher the level of activation during this anticipation, the better the pictures were remembered two weeks later. The study demonstrates how expectancy can affect long-term memory formation, and suggests that the greater our anxiety about a situation, the better we’ll remember that situation. If it’s an unpleasant one, this will only reinforce the anxiety, setting up a vicious cycle. The study has important implications for the treatment of psychological conditions such as post-traumatic stress disorder and social anxiety.
 The effect of anticipation and the specificity of sex differences for amygdala and hippocampus function in emotional memory. Proceedings of the National Academy of Sciences. 103(38), 14200 - 14205.(2006).
Why motivation helps memory
An imaging study has identified the brain region involved in anticipating rewards — specific brain structures in the mesolimbic region involved in the processing of emotions — and revealed how this reward center promotes memory formation. Cues to high-reward scenes that were later remembered activated the reward areas of the mesolimbic region as well as the hippocampus. Anticipatory activation also suggests that the brain actually prepares in advance to filter incoming information rather than simply reacting to the world.
 Reward-Motivated Learning: Mesolimbic Activation Precedes Memory Formation. Neuron. 50(3), 507 - 517.(2006).
Different brain regions for arousing and non-arousing words
An imaging study has found that words representing arousing events (e.g., “rape”, “slaughter”) activate cells in the amygdala, while nonarousing words (e.g., “sorrow”, “mourning”) activated cells in the prefrontal cortex. The hippocampus was active for both type of words. On average, people remembered more of the arousing words than the others, suggesting stress hormones, released as part of the response to emotionally arousing events, are responsible for enhancing memories of those events.
Kensinger, E.A. & Corkin, S. 2004. Two routes to emotional memory: Distinct neural processes for valence and arousal. PNAS, 101, 3310-3315. Published online before print February 23 2004, 10.1073/pnas.0306408101
Short stressful events may improve working memory
We know that chronic stress has a detrimental effect on learning and memory, but a new rat study shows how acute stress (a short, sharp event) can produce a beneficial effect. The rats, trained to a level of 60-70% accuracy on a maze, were put through a 20-minute forced swim before being run through the maze again. Those who experienced this stressful event were better at running the maze 4 hours later, and a day later, than those not forced through the stressful event. It appears that the stress hormone corticosterone (cortisol in humans) increases transmission of the neurotransmitter glutamate in the prefrontal cortex and improves working memory. It also appears that chronic stress suppresses the transmission of glutamate in the prefrontal cortex of male rodents, while estrogen receptors in female rodents make them more resilient to chronic stress than male rats.
 Acute stress enhances glutamatergic transmission in prefrontal cortex and facilitates working memory. Proceedings of the National Academy of Sciences of the United States of America. 106(33), 14075 - 14079.(2009).
Stressed brains rely on habit
And another rat study has found that rats stressed repeatedly and unpredictably for three weeks were more likely than unstressed animals to continue performing habitual behaviors, even when it no longer made sense to do so. This behavior was correlated with reductions in the prelimbic cortex of the medial prefrontal cortex and the dorsomedial striatum (both implicated in goal-directed actions), and increases in the size of the dorsolateral striatum (necessary for habit). The finding follows on from previous research showing that habit formation involves a switch between neural circuits associated with goal-directed behavior and those controlling habitual behavior. The findings have implications for therapies for stress-related disorders and addictive behavior.
 Chronic Stress Causes Frontostriatal Reorganization and Affects Decision-Making. Science. 325(5940), 621 - 625.(2009).
Stress disrupts task-switching, but the brain can bounce back
A new neuroimaging study involving 20 male M.D. candidates in the middle of preparing for their board exams has found that they had a harder time shifting their attention from one task to another after a month of stress than other healthy young men who were not under stress. The finding replicates what has been found in rat studies, and similarly correlates with impaired function in an area of the prefrontal cortex that is involved in attention. However, the brains recovered their function within a month of the end of the stressful period.
 Psychosocial stress reversibly disrupts prefrontal processing and attentional control. Proceedings of the National Academy of Sciences. 106(3), 912 - 917.(2009).
Psychological distress, not depression, linked to increased risk of stroke
A study following 20,627 people for an average of 8.5 years has found that psychological distress was associated with an increased risk of stroke and that the risk of stroke increased the more distress the participants reported. This association remained the same regardless of cigarette smoking, systolic blood pressure, overall blood cholesterol, obesity, previous heart attack, diabetes, social class, education, high blood pressure treatment, family history of stroke and recent antidepressant medication use. However, there was no increased risk for people who had experienced an episode of major depression in the past year or at any point in their lifetime.
 Psychological distress, major depressive disorder, and risk of stroke. Neurology. 70(10), 788 - 794.(2008).
Short-term stress can affect learning and memory
We know that long-lasting, severe stress can impair cell communication in the hippocampus. Now rodent studies have demonstrated that the same outcome can happen with short-term stress. But rather than involving the familiar stress hormone cortisol, acute stress activated corticotropin releasing hormones, which led to the rapid disintegration of dendritic spines in the hippocampus, thus limiting the ability of synapses to collect and store memories.
 Rapid Loss of Dendritic Spines after Stress Involves Derangement of Spine Dynamics by Corticotropin-Releasing Hormone. J. Neurosci.. 28(11), 2903 - 2911.(2008).
Correct levels of stress hormones boost learning
Although it’s known that cortisol production is related to stress and has an impact on learning in humans, that impact is not well understood, because of the difficulties of controlling cortisol levels in humans. A study using ground squirrels has now found that they learn more quickly if they have a modest amount of cortisol, rather than either high or low levels of cortisol.
 Inverted-U shape relationship between cortisol and learning in ground squirrels. Neurobiology of Learning and Memory. 89(4), 582 - 590.(2008).
Stress hormone impacts memory, learning in diabetic rodents
A rodent study sheds light on why diabetes can impair cognitive function. The study found that increased levels of a stress hormone (called cortisol in humans) in diabetic rats impaired synaptic plasticity and reduced neurogenesis in the hippocampus. When levels returned to normal, the hippocampus recovered. Cortisol production is controlled by the hypothalamic-pituitary axis (HPA). People with poorly controlled diabetes often have an overactive HPA axis and excessive cortisol.
 Diabetes impairs hippocampal function through glucocorticoid-mediated effects on new and mature neurons. Nature Neuroscience. 11(3), 309 - 317.(2008).
How stress affects memory
We know stress affects memory. Now a rat study tells us one of the ways it does that. Cell recordings in the hippocampus revealed that, when a mouse moves from one location to another, particular cells fired at each location. When the mouse returned to an earlier location, the same cells fire. However, following stress, the cells that fired in a particular location still fired at the same location, but tended to fire at a different frequency. Stress also reduce the level of LTP at the synapses.
 Stress-induced alterations in hippocampal plasticity, place cells, and spatial memory. Proceedings of the National Academy of Sciences. 104(46), 18297 - 18302.(2007).
Highly accomplished people more prone to failure than others when under stress
One important difference between those who do well academically and those who don’t is often working memory capacity. Those with a high working memory capacity find it easier to read and understand and reason, than those with a smaller capacity. However, a new study suggests there is a downside. Such people tend to heavily rely on their abundant supply of working memory and are therefore disadvantaged when challenged to solve difficult problems, such as mathematical ones, under pressure — because the distraction caused by stress consumes their working memory. They then fall back on the less accurate short-cuts that people with less adequate supplies of working memory tend to use, such as guessing and estimation. Such methods are not made any worse by working under pressure. In the study involving 100 undergraduates, performance of students with strong working memory declined to the same level as those with more limited working memory, when the students were put under pressure. Those with more limited working memory performed as well under added pressure as they did without the stress.
The findings were presented February 17 at the annual meeting of the American Association for the Advancement of Science.
Lifestyle changes improve seniors’ memory surprisingly quickly
A small 14-day study found that those following a memory improvement plan that included memory training, a healthy diet, physical exercise, and stress reduction, showed a 5% decrease in brain metabolism in the dorsal lateral prefrontal region of the brain (involved in working memory) suggesting they were using their brain more efficiently. This change in activity was reflected in better performance on a cognitive measure controlled by this brain region, and participants reported that they felt their memory had improved. The memory training involved doing brainteasers, crossword puzzles and memory exercises. Diet involved eating 5 small meals daily (to prevent fluctuations in blood glucose levels) that were rich in omega-3 fats, low-glycemic index carbohydrates (e.g., whole grains) and antioxidants. Physical exercise involved brisk walking and stretching, and stress reduction involved stretching and relaxation exercises.
The study was presented at the American College of Neuropsychopharmacology's Annual Meeting on December 11-15, in Hawaii.
Stress interferes with problem-solving; Beta-blocker may help
New research suggests that an experience as simple as watching graphically violent or emotional scenes in a movie can induce enough stress to interfere with problem-solving abilities, and that a beta-blocker medication could promote the ability to think flexibly under stressful conditions. Neither the stress nor the beta-blocker affected memory. The research not only has implications for understanding the range of effects of stress on thinking, but could also have broader clinical implications for patients with anxiety disorders or substance abuse problems.
Renner, K., Alexander, J., Hillier, A., Smith, R. & Tivarus, M. 2005. Presented at the annual Society for Neuroscience meeting in Washington, D.C.
Early life stress can lead to memory loss and cognitive decline in middle age
Age-related cognitive decline is probably a result of both genetic and environmental factors. A rat study has demonstrated that some of these environmental factors may occur in early life. Among the rats, emotional stress in infancy showed no ill effects by the time the rats reached adulthood, but as the rats reached middle age, cognitive deficits started to appear in those rats who had had stressful infancies, and progressed much more rapidly with age than among those who had had nurturing infancies. Middle-aged rats who had been exposed to early life emotional stress showed deterioration in brain-cell communication in the hippocampus.
 Mechanisms of Late-Onset Cognitive Decline after Early-Life Stress. J. Neurosci.. 25(41), 9328 - 9338.(2005).
Stress bad for the brain
A study of older adults for three to six years has found that those with continuous high levels of the stress hormone cortisol performed poorly on memory tests and had a 14% smaller hippocampus. A further study involving young adults and children between the ages of six and fourteen found that even an acute increase in cortisol can lead to reversible memory impairments in young adults, and that children from low socio-economic status environments had higher cortisol levels than those from high SES homes. Children from low SES homes tended to process positive and negative attributes more negatively than children from high SES homes, and this type of processing was significantly related to basal cortisol levels at ages 10, 12 and 14.
 Stress hormones and human memory function across the lifespan. Psychoneuroendocrinology. 30(3), 225 - 242.(2005).
Anxiety adversely affects those who are most likely to succeed at exams
It has been thought that pressure harms performance on cognitive skills such as mathematical problem-solving by reducing the working memory capacity available for skill execution. However, a new study of 93 students has found that this applies only to those high in working memory. It appears that the advantage of a high working memory capacity disappears when that attention capacity is compromised by anxiety.
 When high-powered people fail: working memory and "choking under pressure" in math. Psychological Science: A Journal of the American Psychological Society / APS. 16(2), 101 - 105.(2005).
Anxiety good for memory recall, bad for solving complex problems
Cognitive tests given to 19 first-year medical students one to two days before a regular classroom exam, and then a week after the exam, found that, before the exam, students were better able to accurately recall a list of memorized numbers, but did less well on tests that required them to consider many possibilities in order to come up with a reasonable answer. A week after the exam, the opposite was true. It is assumed that the difference in results reflects the effects of stress.
Jessa Alexander & David Beversdorf presented their findings on October 25 in San Diego at the annual Society for Neuroscience conference.
Estrogen effect on memory influenced by stress
The question of whether estrogen helps memory and cognition in women has proven surprisingly difficult to answer, with studies giving conflicting results. Now it seems the answer to that confusion is: it depends. And one of the things it depends on may be the level of stress the woman is experiencing. A rat study has found that the performance of female rats in a water maze was affected by the interaction of hormone level (whether the rat was estrous or proestrous) with water temperature (a source of physical stress). Those rats with high hormone levels did better when the water was warm, while those with low hormone levels did better when the water was cold. The researchers suggest both timing and duration of stress might be factors in determining the effect of hormones on cognition.
 Effect of the Estrous Cycle on Water Maze Acquisition Depends on the Temperature of the Water.. Behavioral Neuroscience. 118(4), 863 - 868.(2004).
Stress reactions no guarantee of authenticity
Physical stress reactions have often been taken as evidence for the authenticity of a memory. A recent study investigated people with “memories” of alien abductions (on the grounds that these are the memories least likely to be true) and found that those who believed they had been abducted by aliens responded physically to recall of that memory in the same way as to recall of other, true, stressful events. The finding suggests that a person’s reaction to a memory is no evidence for whether or not it truly happened.
 Psychophysiological responding during script-driven imagery in people reporting abduction by space aliens. Psychological Science: A Journal of the American Psychological Society / APS. 15(7), 493 - 497.(2004).
Stress no aid to memory
Numerous studies have questioned the accuracy of recall of traumatic events, but the research is often dismissed as artificial and not intense enough to simulate real-life trauma. A new study has used real stress: 509 active duty military personnel enrolled in survival school training were deprived of food and sleep 48 hours and then interrogated. A day later, only 30% of those presented with a line-up could identify the right person, only 34% identified their interrogator from a photo-spread and 49% from single photos shown sequentially (putting the interrogator in the same clothing boosted correct identification to 66%). Thirty people even got the gender wrong. Those subjected to physical threats (half the participants) performed worse.
 Accuracy of eyewitness memory for persons encountered during exposure to highly intense stress. International Journal of Law and Psychiatry. 27(3), 265 - 279.(Submitted).
Anxiety over math blocks learning
The so-called "math block" is notorious - why do we have such a term? Do we talk about a "geography block", or a "physics block"? But we do talk of a reading block. Perhaps the reason for both is the same.
The amount of information you can work with at one time has clear limits, defined by your working memory capacity. When we are anxious, part of our working memory is taken up with our awareness of these fears and worries, leaving less capacity available for processing (which is why students who are very anxious during exams usually perform well below their capabilities). Processes such as reading and working with numbers are very sensitive to working memory capacity because they place such demands on it.
A recently reported study by Mark H. Ashcraft and Elizabeth P. Kirk, both psychologists at Cleveland (Ohio) State University, provides the first solid evidence that, indeed, math-anxious people have working memory problems as they do math.
 The relationships among working memory, math anxiety, and performance. Journal of Experimental Psychology: General. 130(2), 224 - 237.(2001).
Scent of fear impacts cognitive performance
A study involving 75 female students found that those who were exposed to chemicals from fear-induced sweat performed more accurately on word-association tasks than did women exposed to chemicals from other types of sweat or no sweat at all. When processing meaningfully related word pairs, the participants exposed to the fear chemicals were significantly more accurate than those in either the neutral sweat or the control (no-sweat) condition. When processing word pairs that were ambiguous in threat content, such as one neutral word paired with a threatening word or a pair of neutral words, subjects in the fear condition were significantly slower in responding than those in the neutral sweat condition.
Chen, D., Katdare, A. & Lucas, N. 2006. Chemosignals of Fear Enhance Cognitive Performance in Humans. Chemical Senses, Advance Access published on March 9, 2006
Memory of fear more complex than supposed
It seems that fear memory is more complex than has been thought. A new mouse study has shown that not only the hippocampus and amygdala are involved, but that the prefrontal cortex is also critical. The development of the fear association doesn’t occur immediately after a distressing event, but develops over time. The process, it now seems, depends directly on a protein called NR2B.
 Roles of NMDA NR2B Subtype Receptor in Prefrontal Long-Term Potentiation and Contextual Fear Memory. Neuron. 47(6), 859 - 872.(2005).
How trauma triggers long-lasting memories in the brain
A rat study sheds more light on why emotional experiences tend to be better remembered than emotionally neutral events. The study found that emotionally arousing events activated the amygdala, which then increased a specific protein — activity-regulated cytoskeletal protein ("Arc") — in the neurons in the hippocampus. It's thought that Arc helps store these memories by strengthening the synapses.
 Memory-influencing intra-basolateral amygdala drug infusions modulate expression of Arc protein in the hippocampus. Proceedings of the National Academy of Sciences of the United States of America. 102(30), 10718 - 10723.(2005).
Why traumatic memories have the power they do
In the first imaging study to look at retrieval of emotional memories after a long period (one year after encoding), researchers found that people did recall emotional images, both pleasant and unpleasant, better than emotionally-neutral images. This recall was associated with higher activity in both the amygdala and the hippocampus. The synchronicity of activity between these two regions suggested that each region triggers the other, creating a self-reinforcing "memory loop" in which an emotional cue might trigger recall of the event, which then loops back to a re-experiencing of the emotion of the event. The findings suggest why people subject to traumatic events may be trapped in a cycle of emotion and recall that aggravates post-traumatic stress disorder, and may also suggest why therapies in which people relive such memories and reshape perspective to make it less traumatic can help people cope with such memories.
 Remembering one year later: Role of the amygdala and the medial temporal lobe memory system in retrieving emotional memories. Proceedings of the National Academy of Sciences of the United States of America. 102(7), 2626 - 2631.(2005).
Reducing the trauma of traumatic memories
For some, stressful memories can reawaken intense fear, with undesirable consequences. A new study involving mice has found that such stress induces a change in the expression of the acetylcholinesterase gene, which normally produces a vital protein that adheres to neuronal synapses. Following stress, however, the same gene produces large quantities of a protein with modified properties that results in heightened electrical signals in the nerve cells communicating through these synapses. The effect is to create reactions of extreme fright or immobilizing shock. Later encounter with a context which triggers those stressful memories can set off that same neuronal reaction. The researchers have developed an "antisense" agent that acts to neutralize the process whereby the modified protein is produced, thereby preventing the extreme reaction.
 Stress-induced alternative splicing of acetylcholinesterase results in enhanced fear memory and long-term potentiation. Mol Psychiatry. 9(2), 174 - 183.(2003).
Gender & age effects
When emotions involved, older adults may perform memory tasks better than young adults
A study involving 72 young adults (20-30 years old) and 72 older adults (60-75) has found that regulating emotions – such as reducing negative emotions or inhibiting unwanted thoughts – is a resource-demanding process that disrupts the ability of young adults to simultaneously or subsequently perform tasks, but doesn’t affect older adults. In the study, most of the participants watched a two-minute video designed to induce disgust, while the rest watched a neutral two-minute clip. Participants then played a computer memory game. Before playing 2 further memory games, those who had watched the disgusting video were instructed either to change their negative reaction into positive feelings as quickly as possible or to maintain the intensity of their negative reaction, or given no instructions. Those young adults who had been told to turn their disgust into positive feelings, performed significantly worse on the subsequent memory tasks, but older adults were not affected. The feelings of disgust in themselves did not affect performance in either group. It’s speculated that older adults’ greater experience allows them to regulate their emotions without cognitive effort.
 Effects of regulating emotions on cognitive performance: what is costly for young adults is not so costly for older adults. Psychology and Aging. 24(1), 217 - 223.(2009).
Aging brains allow negative memories to fade
Another study has found that older adults (average age 70) remember fewer negative images than younger adults (average age 24), and that this has to do with differences in brain activity. When shown negative images, the older participants had reduced interactions between the amygdala and the hippocampus, and increased interactions between the amygdala and the dorsolateral frontal cortex. It seems that the older participants were using thinking rather than feeling processes to store these emotional memories, sacrificing information for emotional stability. The findings are consistent with earlier research showing that healthy seniors are able to regulate emotion better than younger people.
 Effects of aging on functional connectivity of the amygdala for subsequent memory of negative pictures: a network analysis of functional magnetic resonance imaging data. Psychological Science: A Journal of the American Psychological Society / APS. 20(1), 74 - 84.(2009).
Emotions help memory, at the cost of other memories
Do we remember emotionally charged events better? Maybe — but at a price. A new study presented volunteers with lists of neutral words with one disturbing noun, such as murder or scream, embedded. As expected, the emotional words were much better remembered than the neutral words. More interestingly, the poorest memory occurred for neutral words that were presented immediately before the disturbing words. The effect was greater for women — women forgot those words twice as often as men.
 An emotion-induced retrograde amnesia in humans is amygdala- and beta-adrenergic-dependent. Proceedings of the National Academy of Sciences of the United States of America. 100(23), 13626 - 13631.(2003).
Why women better remember emotional memories
A new brain imaging study reveals gender differences in the encoding of emotional memories. We have long known that women are better at remembering emotional memories, now we can see that the sexes tend to encode emotional experiences in different parts of the brain. In women, it seems that evaluation of emotional experience and encoding of the memory is much more tightly integrated.
 Sex differences in the neural basis of emotional memories. Proceedings of the National Academy of Sciences of the United States of America. 99(16), 10789 - 10794.(2002).
Older adults better at forgetting negative images
It seems that this general tendency, to remember the good, and let the bad fade, gets stronger as we age. Following recent research suggesting that older people tend to regulate their emotions more effectively than younger people, by maintaining positive feelings and lowering negative feelings, researchers examined age differences in recall of positive, negative and neutral images of people, animals, nature scenes and inanimate objects. The first study tested 144 participants aged 18-29, 41-53 and 65-80. Older adults recalled fewer negative images relative to positive and neutral images. For the older adults, recognition memory also decreased for negative pictures. As a result, the younger adults remembered the negative pictures better. Preliminary brain research suggests that in older adults, the amygdala is activated equally to positive and negative images, whereas in younger adults, it is activated more to negative images. This suggests that older adults encode less information about negative images, which in turn would diminish recall.
 Aging and Emotional Memory: The Forgettable Nature of Negative Images for Older Adults. Journal of Experimental Psychology: General. 132(2), 310 - 324.(2003).
Positive stereotypes can offset negative stereotype effect
A number of studies have now shown that negative stereotypes can impair cognitive performance, mainly through adding to working memory load. A new study has now shown that this effect can be mitigated by the activation of a positive stereotype. The research takes advantage of the fact that we all belong to several social groups. In this case, the relevant groups were ‘female’ and ‘college student’. As usual, when (subtly) reminded of negative stereotypes for women and math, women performed worse. The interesting thing was that this didn’t happen if women were also made aware that college students performed better at math than non-college students. Moreover, this was reflected in working memory capacity. It seems that, when both a positive and a negative stereotype are offered, people will tend to choose the positive stereotype, and the effects of this will cancel out the negative stereotype. It’s also worth noting how easily these stereotypes are activated: effects could be manipulated simply by subtly changing demographic questions asked before the test (and it is not uncommon that test-takers are first required to answer some demographic questions).
 Multiple social identities and stereotype threat: Imbalance, accessibility, and working memory.. Journal of Personality and Social Psychology. 96(5), 949 - 966.(2009).
Implicit stereotypes and gender identification may affect female math performance
Another study has come out showing that women enrolled in an introductory calculus course who possessed strong implicit gender stereotypes, (for example, automatically associating "male" more than "female" with math ability and math professions) and were likely to identify themselves as feminine, performed worse relative to their female counterparts who did not possess such stereotypes and who were less likely to identify with traditionally female characteristics. Strikingly, a majority of the women participating in the study explicitly expressed disagreement with the idea that men have superior math ability, suggesting that even when consciously disavowing stereotypes, female math students are still susceptible to negative perceptions of their ability.
 Implicit stereotypes, gender identification, and math-related outcomes: a prospective study of female college students. Psychological Science: A Journal of the American Psychological Society / APS. 18(1), 13 - 18.(2007).
Reducing the racial achievement gap
And staying with the same theme, a study that came out six months ago, and recently reviewed on the excellent new Scientific American Mind Matters blog, revealed that a single, 15-minute intervention erased almost half the racial achievement gap between African American and white students. The intervention involved writing a brief paragraph about which value, from a list of values, was most important to them and why. The intervention improved subsequent academic performance for some 70% of the African American students, but none of the Caucasians. The study was repeated the following year with the same results. It is thought that the effect of the intervention was to protect against the negative stereotypes regarding the intelligence and academic capabilities of African Americans.
 Reducing the Racial Achievement Gap: A Social-Psychological Intervention. Science. 313(5791), 1307 - 1310.(2006).
Women's math performance affected by theories on sex differences
In a salutary reminder to all researchers into gender and race differences, researchers found that women who received a genetic explanation for female underachievement in math or were reminded of the stereotype about female math underachievement, performed more poorly on math tests than those who received an experiential explanation (such as math teachers treating boys preferentially during the first years of math education) or were led to believe there are no sex differences in math.
 Exposure to Scientific Theories Affects Women's Math Performance. Science. 314(5798), 435 - 435.(2006).
Interactions with other races can impair mental capacity in the strongly prejudiced
A new approach on an old theme — the effect of stress on cognitive function. The study looked at the short-term effects of racial prejudice. White college students were assessed for racial bias and then had a conversation with either a black or white person. After the conversation, they were given the Stroop test (participants are presented with color words, which are either in the same color as they name, or not; they are required to respond on the basis of the color of the word, not the name. The test requires a surprising amount of concentration.) For those who had talked with a black person, the greater the amount of racial bias, the worse the student did on the Stroop test. This is assumed to be due to the stress caused by the interaction.
 When prejudice does not pay: Effects of Interracial Contact on Executive Function. Psychological Science. 14(3), 287 - 290.(2003).
A study in which 17 healthy young men were given a nasal spray of either interleukin-6 or a placebo after reading a short story (emotional on one occasion; neutral on the other) before going to bed, has found that those given the immune system molecule showed improved memory for emotional text (but not other kinds of material). Interleukin-6 is involved in inflammatory responses, but recently has also been implicated in memory consolidation during sleep. This finding supports that role, and demonstrates an interaction between the immune system and the central nervous system.
 Enhancing influence of intranasal interleukin-6 on slow-wave activity and memory consolidation during sleep. FASEB J.. 23(10), 3629 - 3636.(2009).
Sleep selectively preserves emotional memories
It’s now generally accepted that sleep plays an important role in consolidating procedural (skill) memories, but the position regarding other types of memory has been less clear. A new study has found that sleep had an effect on emotional aspects of a memory. The study involved showing 88 students neutral scenes (such as a car parked on a street in front of shops) or negative scenes (a badly crashed car parked on a similar street). They were then tested for their memories of both the central objects in the pictures and the backgrounds in the scenes, either after 12 daytime hours, or 12 night-time hours, or 30 minutes after viewing the images, in either the morning or evening. Those tested after 12 daytime hours largely forgot the entire negative scene, forgetting both the central objects and the backgrounds equally. But those tested after a night’s sleep remembered the emotional item (e.g., the smashed car) as well as those who were tested only 30 minutes later. Their memory of the neutral background was however, as bad as the daytime group. The findings are consistent with the view that the individual components of emotional memory become 'unbound' during sleep, enabling the brain to selectively preserve only that information it considers important.
 Sleep preferentially enhances memory for emotional components of scenes. Psychological Science: A Journal of the American Psychological Society / APS. 19(8), 781 - 788.(2008).
Why emotion enhances memory
We know that emotion can increase the memorability of events, but we haven’t known exactly why it does so. Now a new study reveals that during emotional arousal, the stress hormone norepinephrine makes synapses dramatically more sensitive by increasing the number of GluR1 receptors.
 Emotion Enhances Learning via Norepinephrine Regulation of AMPA-Receptor Trafficking. Cell. 131(1), 160 - 173.(2007).
How emotions interfere with memory
We know emotion can interfere with cognitive processes. Now an imaging study adds to our understanding of how that occurs. Emotional images evoked strong activity in typical emotional processing regions (amygdala and ventrolateral prefrontal cortex) while simultaneously deactivating regions involved in memory processing (dorsolateral prefrontal cortex and lateral parietal cortex). The researchers also found individual differences among the subjects in their response to the images. People who showed greater activity in a brain region associated with the inhibition of response to emotional stimuli rated the emotional distracters as less distracting.
 Brain Systems Mediating Cognitive Interference by Emotional Distraction. J. Neurosci.. 26(7), 2072 - 2079.(2006).
Different aspects of attention located in different parts of the brain
We all know attention is important, but we’ve never been sure exactly what it is. Recent research suggests there’s good reason for this – attention appears to be multi-faceted, far less simple than originally conceived. Patients with specific lesions in the frontal lobes and other parts of the brain have provided evidence that different types of attentional problems are associated with injuries in different parts of the brain, suggesting that attention is not, as has been thought, a global process. The researchers have found evidence for at least three distinct processes, each located in different parts of the frontal lobes. These are: (1) a system that helps us maintain a general state of readiness to respond, in the superior medial frontal regions; (2) a system that sets our threshold for responding to an external stimulus, in the left dorsolateral region; and (3) a system that helps us selectively attend to appropriate stimuli, in the right dorsolateral region.
 Dissociations within the anterior attentional system: effects of task complexity and irrelevant information on reaction time speed and accuracy. Neuropsychology. 16(4), 500 - 513.(2002).
How emotions interfere with staying focused
In a new imaging study, Duke University researchers have shown how emotional stimuli and "attentional functions" like driving move in parallel streams through the brain before being integrated in a specific part of the brain's prefrontal cortex (the anterior cingulate, which is located between the right and left halves). Emotional stimuli are thus more likely than simple distractions to interfere with a person's efforts to focus on a task such as driving. These findings may help us understand the neural dynamics underlying emotional distractibility on attentional tasks in affective disorders.
 Dissociable prefrontal brain systems for attention and emotion. Proceedings of the National Academy of Sciences of the United States of America. 99(17), 11447 - 11451.(2002).
Cerebellum implicated in remembering emotions
The part of the brain known as the cerebellum has been most closely associated with motor coordination skills. Experiments with rats suggest that it may also be involved in remembering strong emotions, in particular, in the consolidation of long-term memories of fear.
 Cerebellar role in fear-conditioning consolidation. Proceedings of the National Academy of Sciences of the United States of America. 99(12), 8406 - 8411.(2002).
Amygdala may be critical for allowing perception of emotionally significant events despite inattention
We choose what to pay attention to, what to remember. We give more weight to some things than others. Our perceptions and memories of events are influenced by our preconceptions, and by our moods. Researchers at Yale and New York University have recently published research indicating that the part of the brain known as the amygdala is responsible for the influence of emotion on perception. This builds on previous research showing that the amygdala is critically involved in computing the emotional significance of events. The amygdala is connected to those brain regions dealing with sensory experiences, and the theory that these connections allow the amygdala to influence early perceptual processing is supported by this research. Dr. Anderson suggests that “the amygdala appears to be critical for the emotional tuning of perceptual experience, allowing perception of emotionally significant events to occur despite inattention.”
 Lesions of the human amygdala impair enhanced perception of emotionally salient events. Nature. 411(6835), 305 - 309.(2001).