source memory problems

The fallibility of human memory

I don't often talk about eyewitness testimony, but it's not because of the lack of research. It's a big field, with a lot of research done. When  I say I don't follow it because I regard the main finding as a done deal - eyewitness testimony is useless - that's not meant to denigrate the work being done. There is, clearly, a great deal of value in working out the exact parameters of human failures, and in working out how we can improve eyewitness testimony. I just arbitrarily decided to ignore this area of research until they'd sorted it all out!

Negative stereotypes about aging affect how well older adults remember

Another study has come out supporting the idea that negative stereotypes about aging and memory affect how well older adults remember. In this case, older adults reminded of age-related decline were more likely to make memory errors.

In the study, 64 older adults (60-74; average 70) and 64 college students were compared on a word recognition task. Both groups first took a vocabulary test, on which they performed similarly. They were then presented with 12 lists of 15 semantically related words. For example, one list could have words associated with "sleep," such as "bed," "rest," "awake," "tired" and "night" — but not the word “sleep”. They were not told they would be tested on their memory of these, rather they were asked to rate each word for pleasantness.

They then engaged in a five-minute filler task (a Sudoku) before a short text was read to them. For some, the text had to do with age-related declines in memory. These participants were told the experiment had to do with memory. For others, the text concerned language-processing research. These were told the experiment had to do with language processing and verbal ability.

They were then given a recognition test containing 36 of the studied words, 48 words unrelated to the studied words, and 12 words related to the studied words (e.g. “sleep”). After recording whether or not they had seen each word before, they also rated their confidence in that answer on an 8-point scale. Finally, they were given a lexical decision task to independently assess stereotype activation.

While young adults showed no effects from the stereotype manipulation, older adults were much more likely to falsely recognize related words that had not been studied if they had heard the text on memory. Those who heard the text on language were no more likely than the young adults to falsely recognize related words.

Note that there is always quite a high level of false recognition of such items: young adults, and older adults in the low-threat condition falsely recognized around half of the related lures, compared to around 10% of unrelated words. But in the high-threat condition, older adults falsely recognized 71% of the related words.

Moreover, older adults’ confidence was also affected. While young adults’ confidence in their false memories was unaffected by threat condition, older adults in the high-threat condition were more confident of their false memories than older adults in the low-threat condition.

The idea that older adults were affected by negative stereotypes about aging was supported by the results of the lexical decision task, which found that, in the high-threat condition, older adults responded more quickly to words associated with negative stereotypes than to neutral words (indicating that they were more accessible). Young adults did not show this difference.

Reference: 

Thomas, A. K., & Dubois, S. J. (2011). Reducing the burden of stereotype threat eliminates age differences in memory distortion. Psychological science, 22(12), 1515-7. doi:10.1177/0956797611425932

News Topic aging - specific failures

Older news items (pre-2010) brought over from the old website

More evidence the aging brain is easily distracted

Here’s another study demonstrating that older adults aren't able to filter out distracting information as well as younger adults. The imaging study compared face recognition performance in younger adults (average age 26) and older (average age 70). It was found that, for both groups, difficulties encoding a new face were marked by decreased activity in the hippocampus. But older brains also showed increased activation in the auditory cortex, left prefrontal cortex and medial parietal cortex, showing that they were processing too much irrelevant information from their external environment – the notoriously loud noise of the scanner. Apart from confirming the distractibility of the older brain, the finding also raises questions about imaging studies in general, for older adults. It’s likely that older adults’ cognitive performance have been systematically underestimated.

[520] Stevens, D. W., Hasher L., Chiew K. S., & Grady C. L. (2008).  A Neural Mechanism Underlying Memory Failure in Older Adults. J. Neurosci.. 28(48), 12820 - 12824.

http://www.eurekalert.org/pub_releases/2008-11/bcfg-sfm112408.php

Age-related memory loss tied to slip in filtering information quickly

Increasing research in recent years has concluded that one of the problems for the aging brain is a diminished ability to ignore irrelevant information. In fact, many believe it is the major problem for the healthy aging brain. Others believe, more traditionally, that the main problem is a decline in processing speed. A new study shows that both of these happen — in tandem. The difficulty in suppressing irrelevant information occurs because the processing of that irrelevant information has slowed down. This slowdown, at least in visual memory, seems to occur only in the first 200 milliseconds of visual processing, and the difficulty in suppressing irrelevant information occurs only during this period. This suppression failure is thought to impact on working memory.

[553] Gazzaley, A., Clapp W., Kelley J., McEvoy K., Knight R. T., & D'Esposito M. (2008).  Age-related top-down suppression deficit in the early stages of cortical visual memory processing. Proceedings of the National Academy of Sciences. 105(35), 13122 - 13126.

http://www.eurekalert.org/pub_releases/2008-09/uoc--aml090208.php

More on why older adults are more distractible

A number of recent studies have made it clear that as we age, we find it harder to block out unwanted distractions. A new study used a new brain imaging technique known as EROS to determine whether this is due to faster sensory memory decay or to inefficient filtering of irrelevant sensory information. The study involved 16 young and 16 older participants who read a book of their choice while distracting tones played in the background. The volume of the tones was adjusted so that all the participants heard them at the same level, and the tones were emitted in groups of fives. The young participants showed brain activity in the auditory cortex in response to the first tone in each sequence only, but the older adults' brains responded to all five. The finding supports the view that the growing difficulty at blocking out distractions is due to inefficient filtering of irrelevant sensory information , not faster sensory memory decay.

[1380] Fabiani, M., Low K. A., Wee E., Sable J. J., & Gratton G. (2006).  Reduced Suppression or Labile Memory? Mechanisms of Inefficient Filtering of Irrelevant Information in Older Adults. Journal of Cognitive Neuroscience. 18(4), 637 - 650.

http://www.sciencentral.com/articles/view.htm3?article_id=218392783

Why older adults more vulnerable to distraction from irrelevant information

We know older adults find it harder to filter out irrelevant information. Now a study looking at brain function in young, middle-aged and older adults has identified changes in brain activity that begin gradually in middle age which may explain why. In younger adults, activity in the dorsolateral prefrontal cortex (associated with tasks that require concentration, such as reading) normally increases during the task, while activity in the medial frontal and parietal regions (associated with non-task related activity in a resting state, such as thinking about yourself, what you did last night, monitoring what's going on around you) normally decreases. In middle age (40-60 years), this pattern begins to break down during performance of memory tasks, although performance is not affected (but most of the participants were fairly well educated, so the finding of brain changes without accompanying behavioural changes in the middle-aged group may reflect the "protective effect" of education). Activity in the medial frontal and parietal regions stays turned on while activity in the dorsolateral prefrontal cortex decreases. The imbalance becomes more pronounced in older adults (65+), suggesting there is a gradual, age-related reduction in the ability to suspend non-task-related or "default-mode" activity and engage areas for carrying out memory tasks.

[759] Grady, C. L., Springer M. V., Hongwanishkul D., McIntosh A. R., & Winocur G. (2006).  Age-related Changes in Brain Activity across the Adult Lifespan. Journal of Cognitive Neuroscience. 18(2), 227 - 241.

http://www.eurekalert.org/pub_releases/2006-02/b-oam013006.php

Changes in brain, not age, determine one's ability to focus on task

It’s been established that one of the reasons why older adults may do less well on cognitive tasks is because they have greater difficulty in ignoring distractions, which impairs their concentration. But not all older people are afflicted by this. Some are as focused as young adults. An imaging study has now revealed a difference between the brains of those people who are good at focusing, and those who are poor. Those who have difficulty screening out distractions have less white matter in the frontal lobes. They activated neurons in the left frontal lobe as well as the right. Young people and high-functioning older adults tended to use only the right frontal lobe.

[1117] Colcombe, S. J., Kramer A. F., Erickson K. I., & Scalf P. (2005).  The implications of cortical recruitment and brain morphology for individual differences in inhibitory function in aging humans. Psychology and Aging. 20(3), 363 - 375.

http://www.eurekalert.org/pub_releases/2005-10/uoia-cib102605.php

Memory loss in older adults due to distractions, not inability to focus

We know that older adults often have short-term memory problems, and this has been linked to problems with attention. An imaging study now provides evidence that these short-term memory problems are associated with an inability to filter out surrounding distractions, rather than problems with focusing attention. It’s been suggested that an inability to ignore distracting information may indeed be at the heart of many of the cognitive problems that accompany aging. It should be noted that this is not an inevitable effect of age — in the study, 6 of the 16 older adults involved had no problems with short-term memory or attention.

[383] Gazzaley, A., Cooney J. W., Rissman J., & D'Esposito M. (2005).  Top-down suppression deficit underlies working memory impairment in normal aging. Nat Neurosci. 8(10), 1298 - 1300.

http://www.eurekalert.org/pub_releases/2005-09/uoc--mli090805.php

Older news items (pre-2010) brought over from the old website

Older adults more likely to "remember" misinformation

In a study involving older adults (average age 75) and younger adults (average age 19), participants studied lists of paired related words, then viewed new lists of paired words, some the same as before, some different, and some with only one of the two words the same. In those cases, the "prime" word, which was presented immediately prior to the test, was plausible but incorrect. The older adults were 10 times more likely than young adults to accept the wrong word and falsely "remember" earlier studying that word. This was true even though older adults had more time to study the list of word pairs and attained a performance level equal to that of the young adults. Additionally, when told they had the option to "pass" when unsure of an answer, older adults rarely used the option. Younger adults did, greatly reducing their false recall. The findings reflect real-world reports of a rising incidence of scams perpetrated on the elderly, which rely on the victim’s poor memory and vulnerability to the power of suggestion.

[629] Jacoby, L. L., Bishara A. J., Hessels S., & Toth J. P. (2005).  Aging, subjective experience, and cognitive control: dramatic false remembering by older adults. Journal of Experimental Psychology. General. 134(2), 131 - 148.

http://www.eurekalert.org/pub_releases/2005-05/apa-gmc051005.php

Repeated product warnings are remembered as product recommendations

Warnings about particular products may have quite the opposite effect than intended. Because we retain a familiarity with encountered items far longer than details, the more often we are told a claim about a consumer item is false, the more likely we are to accept it as true a little further down the track. Research also reveals that older adults are more susceptible to this error. It is relevant to note that in the U.S. at least, some 80% of consumer fraud victims are over 65.

[489] Skurnik, I., Yoon C., Park D. C., & Schwarz N. (2005).  How Warnings about False Claims Become Recommendations. Journal of Consumer Research. 31(4), 713 - 724.

http://www.eurekalert.org/pub_releases/2005-03/uocp-nrr032905.php

Source-memory problems not an inevitable consequence of aging, but a function of frontal-lobe efficiency

Source memory is memory for the broad contextual aspects surrounding an event, such as who was speaking, or whether you learned something from a book or TV. Previous research has found that it is in this aspect of memory that older people tend to be particularly poor. In a study that compared older individuals with undergraduates, it was found that those who performed above average on frontal-lobe tests, showed no significant impairment of source memory, regardless of age. Those with below-average performance, tended to have impaired source memory (as a group). In other words, source-memory problems are not an inevitable consequence of aging, as has been widely thought, but rather are a function of frontal-lobe efficiency. The proportion of older adults who experience frontal-lobe decline, at what ages, and to what degree, is unknown at this time.
What’s more, when researchers required people to consider the relation between an item and its context (source), age differences in memory performance completely disappeared, suggesting older adults can learn strategies to remember the context better.

[626] Glisky, E. L., Rubin S. R., & Davidson P. S. R. (2001).  Source Memory in Older Adults: An Encoding or Retrieval Problem?. Journal of Experimental Psychology: Learning, Memory, and Cognition. 27(5), 1131 - 1146.

http://www.eurekalert.org/pub_releases/2001-09/apa-ada083101.php

Older news items (pre-2010) brought over from the old website

Genetic cause for word-finding disease

Primary Progressive Aphasia is a little-known form of dementia in which people lose the ability to express themselves and understand speech. People can begin to show symptoms of PPA as early as in their 40's and 50's. A new study has found has discovered a gene mutation in two unrelated families in which nearly all the siblings suffered from PPA. The mutations were not observed in the healthy siblings or in more than 200 controls.

[1164] Hutton, M. L., Graff-Radford N. R., Mesulam M. Marsel, Johnson N., Krefft T. A., Gass J. M., et al. (2007).  Progranulin Mutations in Primary Progressive Aphasia: The PPA1 and PPA3 Families. Arch Neurol. 64(1), 43 - 47.

http://www.eurekalert.org/pub_releases/2007-01/nu-rdg011507.php

Word substitution mistakes have more to do with speech planning than with thought or attention problems

Why is it that we can look at something, know what it is and still call it by the wrong name? A new study suggests that the problem doesn’t lie in haste or a lack of attention, but rather in a fault in speech planning.

Griffin, Z.M. 2004. The eyes are right when the mouth is wrong. Psychological Science, 15 (12), 814-820.

http://www.eurekalert.org/pub_releases/2004-12/aps-sot120804.php

What causes word finding failures in young and older adults

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Older people with the 'Alzheimer's gene' find it harder to remember intentions

It has been established that those with a certain allele of a gene called ApoE have a much greater risk of developing Alzheimer’s (those with this allele on both genes have 8 times the risk; those with the allele on one gene have 3 times the risk). Recent studies also suggest that such carriers are also more likely to show signs of deficits in episodic memory – but that these deficits are quite subtle. In the first study to look at prospective memory in seniors with the “Alzheimer’s gene”, involving 32 healthy, dementia-free adults between ages of 60 and 87, researchers found a marked difference in performance between those who had the allele and those who did not. The results suggest an exception to the thinking that ApoE status has only a subtle effect on cognition.

[1276] Driscoll, I., McDaniel M. A., & Guynn M. J. (2005).  Apolipoprotein E and prospective memory in normally aging adults. Neuropsychology. 19(1), 28 - 34.

http://www.eurekalert.org/pub_releases/2005-01/apa-opw011805.php

'Imagination' helps older people remember to comply with medical advice

A new study suggests a way to help older people remember to take medications and follow other medical advice. Researchers found older adults (aged 60 to 81) who spent a few minutes picturing how they would test their blood sugar were 50% more likely to actually do these tests on a regular basis than those who used other memory techniques. Participants were assigned to one of three groups. One group spent one 3-minute session visualizing exactly what they would be doing and where they would be the next day when they were scheduled to test their blood sugar levels. Another group repeatedly recited aloud the instructions for testing their blood. The last group were asked to write a list of pros and cons for testing blood sugar. All participants were asked not to use timers, alarms or other devices. Over 3 weeks, the “imagination” group remembered 76% of the time to test their blood sugar at the right times of the day compared to an average of 46% in the other two groups. They were also far less likely to go an entire day without testing than those in the other two groups.

[473] Liu, L. L., & Park D. C. (2004).  Aging and medical adherence: the use of automatic processes to achieve effortful things. Psychology and Aging. 19(2), 318 - 325.

http://www.eurekalert.org/pub_releases/2004-06/nioa-ho060104.php

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Older news items (pre-2010) brought over from the old website

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Older news items (pre-2010) brought over from the old website

Errorless learning not always best for older brains

New evidence challenges the view that older adults learn best through errorless learning. Trial-and-error learning can be better if done the right way.

Following a 1994 study that found that errorless learning was better than trial-and-error learning for amnesic patients and older adults, errorless learning has been widely adopted in the rehabilitation industry. Errorless learning involves being told the answer without repeatedly trying to answer the question and perhaps making mistakes. For example, in the 1994 study, participants in the trial-and-error condition could produce up to three errors in answer to the question “I am thinking of a word that begins with QU”, before being told the answer was QUOTE; in contrast, participants in the errorless condition were simply told “I am thinking of a word that begins with QU and it is ‘QUOTE’.”

In a way, it is surprising that errorless learning should be better, given that trial-and-error produces much deeper and richer encoding, and a number of studies with young adults have indeed found an advantage for making errors. Moreover, it’s well established that retrieving an item leads to better learning than passively studying it, even when you retrieve the wrong item. This testing effect has also been found in older adults.

In another way, the finding is not surprising at all, because clearly the trial-and-error condition offers many opportunities for confusion. You remember that QUEEN was mentioned, for example, but you don’t remember whether it was a right or wrong answer. Source memory, as I’ve often mentioned, is particularly affected by age.

So there are good theoretical reasons for both positions regarding the value of mistakes, and there’s experimental evidence for both. Clearly it’s a matter of circumstance. One possible factor influencing the benefit or otherwise of error concerns the type of processing. Those studies that have found a benefit have generally involved conceptual associations (e.g. What’s Canada’s capital? Toronto? No, Ottawa). It may be that errors are helpful to the extent that they act as retrieval cues, and evoke a network of related concepts. Those studies that have found errors harm learning have generally involved perceptual associations, such as word stems and word fragments (e.g., QU? QUeen? No, QUote). These errors are arbitrary, produce interference, and don’t provide useful retrieval cues.

So this new study tested the idea that producing errors conceptually associated with targets would boost memory for the encoding context in which information was studied, especially for older adults who do not spontaneously elaborate on targets at encoding.

In the first experiment, 33 young (average age 21) and 31 older adults (average age 72) were shown 90 nouns presented in three different, intermixed conditions. In the read condition (designed to provide a baseline), participants read aloud the noun fragment presented without a semantic category (e.g., p­_g). In the errorless condition, the semantic category was presented with the target word fragment (e.g. a farm animal  p­_g), and the participants read aloud the category and their answer. The category and target were then displayed. In the trial-and-error condition, the category was presented and participants were encouraged to make two guesses before being shown the target fragment together with the category. The researchers changed the target if it was guessed. Participants were then tested using a list of 70 words, of which 10 came from each of the study conditions, 10 were new unrelated words, and 30 were nontarget exemplars from the TEL categories. Those that the subject had guessed were labeled as learning errors; those that hadn’t come up were labeled as related lures. In addition to an overall recognition test (press “yes” to any word you’ve studied and “no” to any new word), there were two tests that required participants to endorse items that were studied in the TEL condition and reject those studied in the EL condition, and vice versa.

The young adults did better than the older on every test. TEL produced better learning than EL, and both produced better learning than the read condition (as expected). The benefit of TEL was greater for older adults. This is in keeping with the idea that generating exemplars of a semantic category, as occurs in trial-and-error learning, helps produce a richer, more elaborated code, and that this is of greater to older adults, who are less inclined to do this without encouragement.

There was a downside, however. Older adults were also more prone to falsely endorsing prior learning errors or semantically-related lures. It’s worth noting that both groups were more likely to falsely endorse learning errors than related lures.

But the main goal of this first experiment was to disentangle the contributions of recollection and familiarity to the two types of learning. It turns out that there was no difference between young and older adults in terms of familiarity; the difference in performance between the two groups stemmed from recollection. Recollection was a problem for older adults in the errorless condition, but not in the trial-and-error condition (where the recollective component of their performance matched that of young adults). This deficit is clearly closely related to age-related deficits in source memory.

It was also found that familiarity was marginally more important in the errorless condition than the trial-and-error condition. This is consistent with the idea that targets learned without errors acquire greater fluency than those learned with errors (with the downside that they don’t pick up those contextual details that making errors can provide).

In the second experiment, 15 young and 15 older adults carried out much the same procedure, except that during the recognition test they were also required to mention the context in which the words were learned was tested (that is, were the words learned through trial-and-error or not).

Once again, trial-and-error learning was associated with better source memory relative to errorless learning, particularly for the older adults.

These results support the hypothesis that trial-and-error learning is more beneficial than errorless learning for older adults when the trials encourage semantic elaboration. But another factor may also be involved. Unlike other errorless studies, participants were required to attend to errors as well as targets. Explicit attention to errors may help protect against interference.

In a similar way, a recent study involving young adults found that feedback given in increments (thus producing errors) is more effective than feedback given all at once in full. Clearly what we want is to find that balance point, where elaborative benefits are maximized and interference is minimized.

Reference: 

[2496] Cyr, A. - A., & Anderson N. D. (2011).  Trial-and-error learning improves source memory among young and older adults. Psychology and Aging. No Pagination Specified - No Pagination Specified.

Ability to remember memories' origin develops slowly

A study comparing the brains of children, adolescents, and young adults has found that the ability to remember the origin of memories is slow to mature. As with older adults, impaired source memory increases susceptibility to false memories.

In the study, 18 children (aged 7-8), 20 adolescents (13-14), and 20 young adults (20-29) were shown pictures and asked to decide whether it was a new picture or one they had seen earlier. Some of the pictures were of known objects and others were fanciful figures (this was in order to measure the effects of novelty in general). After a 10-minute break, they resumed the task — with the twist that any pictures that had appeared in the first session should be judged “new” if that was the first appearance in the second session. EEG measurements (event-related potentials — ERPs) were taken during the sessions.

ERPs at the onset of a test stimulus (each picture) are different for new and old (repeated) stimuli. Previous studies have established various old/new effects that reflect item and source memory in adults. In the case of item memory, recognition is thought to be based on two processes — familiarity and recollection — which are reflected in ERPs of different timings and location (familiarity: mid-frontal at 300-500 msec; recollection: parietal at 400-70 msec). Familiarity is seen as a fast assessment of similarity, while recollection varies according to the amount of retrieved information.

Source memory appears to require control processes that involve the prefrontal cortex. Given that this region is the slowest to mature, it would not be surprising if source memory is a problematic memory task for the young. And indeed, previous research has found that children do have particular difficulty in sourcing memories when the sources are highly similar.

In the present study, children performed more poorly than adolescents and adults on both item memory and source memory. Adolescents performed more poorly than adults on item memory but not on source memory. Children performed more poorly on source memory than item memory, but adolescents and adults showed no difference between the two tasks.

All groups responded faster to new items than old, and ERP responses to general novelty were similar across the groups — although children showed a left-frontal focus that may reflect the transition from analytic to a more holistic processing approach.

ERPs to old items, however, showed a difference: for adults, they were especially pronounced at frontal sites, and occurred at around 350-450 msec; for children and adolescents they were most pronounced at posterior sites, occurring at 600-800 msec for children and 400-600 msec for adolescents. Only adults showed the early midfrontal response that is assumed to reflect familiarity processing. On the other hand, the late old/new effect occurring at parietal sites and thought to reflect recollection, was similar across all age groups. The early old/new effect seen in children and adolescents at central and parietal regions is thought to reflect early recollection.

In other words, only adults showed the brain responses typical of familiarity as well as recollection. Now, some research has found evidence of familiarity processing in children, so this shouldn’t be taken as proof against familiarity processing in the young. What seems most likely is that children are less likely to use such processing. Clearly the next step is to find out the factors that affect this.

Another interesting point is the early recollective response shown by children and adolescents. It’s speculated that these groups may have used more retrieval cues — conceptual as well as perceptual — that facilitated recollection. I’m reminded of a couple of studies I reported on some years ago, that found that young children were better than adults on a recognition task in some circumstances — because children were using a similarity-based process and adults a categorization-based one. In these cases, it had more to do with knowledge than development. I’ve appended the two reports below.

It’s also worth noting that, in adults, the recollective response was accentuated in the right-frontal area. This suggests that recollection was overlapping with post-retrieval monitoring. It’s speculated that adults’ greater use of familiarity produces a greater need for monitoring, because of the greater uncertainty.

What all this suggests is that preadolescent children are less able to strategically recollect source information, and that strategic recollection undergoes an important step in early adolescence that is probably related to improvements in cognitive control. But this process is still being refined in adolescents, in particular as regards monitoring and coping with uncertainty.

Interestingly, source memory is also one of the areas affected early in old age.

Failure to remember the source of a memory has many practical implications, in particular in the way it renders people more vulnerable to false memories.

 

Children outperform adults in memory study

An example of the perils of knowing too much! — under specific conditions, young children can beat most adults on a recognition memory test. The study compared young children (average age 5 years) with college students. Without being told what was being tested, participants were shown pictures of cats, bears and birds. Some of them were first shown a picture of a cat, and told that it had “beta cells inside its body”. They were then shown other pictures, and asked whether these animals also had beta cells. After this, they were shown other pictures, and asked whether they had been shown them before. The children were accurate on average 31% of the time; the college students only 7% of the time. The researchers suggested the reason was because the children used similarity-based induction: when asked whether each pictured animal had "beta cells", they looked carefully to see if the animal looked similar to the original cat. On the other hand, the adults used category-based induction: once they determined whether the animal pictured was a cat or not, they paid no more attention. Thus, when they were tested later, the adults didn't know the pictures as well as the children. A subsequent study taught the children to use category-based induction. Their performance then dropped to the level of the adults. Another study in which participants were simply shown the pictures of the 30 animals and told to remember them for a recognition test, found adults were accurate 42% of the time, compared to only 27% for the children.

http://tinyurl.com/55r4n

http://www.eurekalert.org/pub_releases/2004-07/osu-cch072104.php

Too much knowledge can be bad for some types of memory

Following on from an earlier study reported last year, in which children were found to have better memories than adults in certain circumstances, researchers have found that adults did better remembering pictures of imaginary animals than they did remembering pictures of real cats. The reason has to do with the effects of categorization. While categorization is often vital, it can lead people to ignore individual details. The trick is to know when it’s important to categorize and when it’s better to note specific details. The new study added to the earlier findings by showing that there is a gradual decrease in recognition memory from children to adults, rather than an abrupt change in the way people see the world. Moreover, the difference in how adults and children perceive and remember objects is not a developmental difference, but one caused by differences in knowledge. Adults performed like children when shown imaginary animals.

http://www.eurekalert.org/pub_releases/2005-05/osu-tmk051005.php

Whether couple’s collaborative dialogue helps spouse's memory

A small study suggests that middle-aged couples are more likely to be effective than older couples in helping fill in each other’s memory gaps, but effective collaboration also depends on conversational style.

In my book on remembering what you’re doing and what you intend to do, I briefly discuss the popular strategy of asking someone to remind you (basically, whether it’s an effective strategy depends on several factors, of which the most important is the reliability of the person doing the reminding). So I was interested to see a pilot study investigating the use of this strategy between couples.

The study confirms earlier findings that the extent to which this strategy is effective depends on how reliable the partner's memory is, but expands on that by tying it to age and conversational style.

The study involved 11 married couples, of whom five were middle-aged (average age 52), and six were older adults (average age 73). Participants completed a range of prospective memory tasks by playing the board game "Virtual Week," which encourages verbal interaction among players about completing real life tasks. For each virtual "day" in the game, participants were asked to perform 10 different prospective memory tasks — four that regularly occur (eg, taking medication with breakfast), four that were different each day (eg, purchasing gasoline for the car), and two being time-check tasks that were not based on the activities of the board game (eg, check lung capacity at two specified times).

Overall, the middle-aged group benefited more from collaboration than the older group. But it was also found that those couples who performed best were those who were more supportive and encouraging of each other.

Collaboration in memory tasks is an interesting activity, because it can be both helpful and hindering. Think about how memory works — by association. You start from some point, and if you’re on a good track, more and more should be revealed as each memory triggers another. If another person keeps interrupting your train, you can be derailed. On the other hand, they might help you fill you in gaps that you need, or even point you to the right track, if you’re on the wrong one.

In this small study, it tended to be the middle-aged couples that filled in the gaps more effectively than the older couples. That probably has a lot to do with memory reliability. So it’s not a big surprise (though useful to be aware of). But what I find more interesting (because it’s less obvious, and more importantly, because it’s more under our control) is this idea that our conversational style affects whether memory collaboration is useful or counterproductive. I look forward to results from a larger study.

Reference: 

[2490] Margrett, J. A., Reese-Melancon C., & Rendell P. G. (2011).  Examining Collaborative Dialogue Among Couples. Zeitschrift für Psychologie / Journal of Psychology. 219, 100 - 107.

Have I done it?

Watching another person do something can leave you with the memory of having done it yourself.

I’m not at all sure why the researcher says they were “stunned” by these findings, since it doesn’t surprise me in the least, but a series of experiments into the role of imagination in creating false memories has revealed that people who had watched a video of someone else doing a simple action often remembered doing the action themselves two weeks later. In fact in my book on remembering intentions, which includes a chapter on remembering whether you’ve done something, I mention the risk of imagining yourself doing something (that you then go on to believe you have actually done it), and given all the research on mirror neurons, it’s no big step to go from watching someone doing something to remembering that you did it. Nevertheless, it’s nice to get the confirmation.

The experiments involved participants performing several simple actions, such as shaking a bottle or shuffling a deck of cards. Then they watched videos of someone else doing simple actions—some of which they had performed themselves and some of which they hadn’t. Two weeks later, they were asked which actions they had done. They were much more likely to falsely remember doing an action if they had watched someone else do it — even when they had been warned about the effect.

It seems likely that this is an unfortunate side-effect of a very useful ability — namely our ability to learn motor skills by observing others (using the aforesaid mirror neurons) — and there’s probably not a great deal we can do to prevent it happening. It’s just a reminder of how easy it is to form false memories.

Reference: 

[1839] Lindner, I., Echterhoff G., Davidson P. S. R., & Brand M. (2010).  Observation Inflation. Psychological Science. 21(9), 1291 - 1299.

The problem of 'destination amnesia'

Two studies demonstrate why knowing whether you’ve told someone something is difficult for all of us, and that this is particularly so as you get older.

A number of studies have found that source memory (knowing where you heard/read/experienced something) is a particular problem for older adults. Destination memory (knowing who you’ve told) is an area that has been much less studied. Last year I reported on why destination memory is difficult for all of us (my report is repeated below). A follow-up study has found not only that destination memory is a particular problem for older adults, but that it is in fact a worse problem than source memory. Moreover, destination amnesia (falsely believing you've told someone something) is not only more common among older adults, but is associated with greater confidence in the false belief.

The study compared the performance of 40 students (aged 18-30) and 40 healthy older adults (aged 60-83). In the first task, the participant read out loud 50 interesting facts to 50 celebrities (whose faces appeared on a computer screen), and were then tested on their memory of which fact they told to which famous person. In the second task, they had to remember which famous person told them which particular fact. Older adults' performance was 21% worse than their younger counterparts on the destination memory test, but only 10% worse (50% vs 60%) on the source memory test. This latter difference was not statistically significant.

The 2009 study, involving 60 students, found good reason for destination memory to be so poor — apparently outgoing information is less integrated with context than incoming information is. In the study, 50 random facts were linked with the faces of 50 famous people; half the students then “told” each fact to one of the faces, reading it aloud to the celebrity’s picture. The other half read each fact silently and saw a different celebrity moments afterward. In the subsequent memory test, students who simulated telling the facts did 16% worse. In another experiment using personal facts, it was significantly worse.

However, the final experiment found that you could improve your destination memory by saying the name of the person you’re speaking to, as you tell them. The findings also suggest that self-focus is an important factor: increasing self-focus (e.g. by telling a personal story) worsened destination memory; reducing self-focus (e.g. by naming the listener) improved it.

Reference: 

[1809] Gopie, N., Craik F. I. M., & Hasher L. (2010).  Destination memory impairment in older people.. Psychology and Aging.

[396] Gopie, N., & MacLeod C. M. (2009).  Destination Memory: Stop Me if I've Told You This Before. Psychological Science. 20(12), 1492 - 1499.

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