Source Memory Problems

Mindfulness meditation is associated with various positive benefits, one of which is improved attention, but it might not be all good. A new study suggests that it may have negative cognitive consequences.

The study included three experiments, in the first two of which undergraduates carried out a 15-minute guided exercise: one group was instructed to focus attention on their breathing without judgment (mindfulness group); the other group was told to think about whatever came to mind (mind-wandering group; the control).

In the first experiment, 153 participants then studied a list of 15 words related to the concept of trash, but not including the word "trash". When then asked to recall as many of the words from the list as they could remember, 39% of the mindfulness group falsely recalled seeing the word "trash" on the list compared to only 20% of the mind-wandering group. There was no difference between the groups in the number of other words falsely recalled.

In the second experiment, 140 participants were compared to themselves, before and after the intervention. They all began by doing six of the same sort of word lists. They were then randomly assigned either the meditation exercise or the mind-wandering. This was then followed by a further six word lists.

Again, mindfulness participants were more likely to falsely recall the critical word than those who engaged in mind wandering. Those in the mind-wandering group showed no difference in performance on the word lists before and after, while those in the meditation group were significantly more likely to falsely remember the critical item. Again, there were no other differences in performance between the groups: they correctly recalled about the same number of words, and they falsely remembered about the same number of other words.

In the third experiment, 215 undergraduates had to determine whether a word had been presented earlier, where the words shown were all part of a strongly associated pair (e.g., foot-shoe). After seeing the 100 words (for 1.5 seconds each), they were then tested. Each word had an equal chance of being one of the words in the presented list, or its associated pair. All students were then given the 15-minute meditation exercise, before going through the process again.

Again, the rate of words correctly identified as seen before was about the same before and after the meditation exercise, but the rate of words falsely identified increased significantly after the exercise.

In all, then, it seems that mindfulness meditation increased participants' susceptibility to false memories, reducing their ability to differentiate items they actually encountered from items they only imagined (because of their strong association to the items encountered).

The researchers speculate that the mechanism that seems to underlie the benefits of mindfulness — judgment-free thoughts and feelings — might also affect people's ability to determine the origin of a given memory (source memory), because they have become less able to distinguish between externally occurring events and internally generated events.

Source memory is one of those memory domains that tend to be affected by aging. However, the benefits of meditation for improving attention — another area particularly affected by age — outweigh this downside. So I'm certainly not suggesting anyone should be put off by this finding!

An interesting question that remains to be answered is whether this negative effect on source memory is short-lived, or whether experienced meditators tend to have poorer source memory.

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.

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

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.

[2496] Cyr A-A, Anderson ND. Trial-and-error learning improves source memory among young and older adults. Psychology and Aging. 2011 :No Pagination Specified - No Pagination Specified.

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.

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.

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.

[2490] Margrett JA, Reese-Melancon C, Rendell PG. Examining Collaborative Dialogue Among Couples. Zeitschrift für Psychologie / Journal of Psychology [Internet]. 2011 ;219:100 - 107. Available from:

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.

[1839] Lindner I, Echterhoff G, Davidson PSR, Brand M. Observation Inflation. Psychological Science [Internet]. 2010 ;21(9):1291 - 1299. Available from:

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.

[1809] Gopie N, Craik FIM, Hasher L. Destination memory impairment in older people. Psychology and Aging [Internet]. 2010 . Available from:

[396] Gopie N, MacLeod CM. Destination Memory: Stop Me if I've Told You This Before. Psychological Science [Internet]. 2009 ;20(12):1492 - 1499. Available from:

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 LL, Bishara AJ, Hessels S, Toth JP. Aging, subjective experience, and cognitive control: dramatic false remembering by older adults. Journal of Experimental Psychology. General [Internet]. 2005 ;134(2):131 - 148. Available from:

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 DC, Schwarz N. How Warnings about False Claims Become Recommendations. Journal of Consumer Research [Internet]. 2005 ;31(4):713 - 724. Available from:

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 EL, Rubin SR, Davidson PSR. Source Memory in Older Adults: An Encoding or Retrieval Problem?. Journal of Experimental Psychology: Learning, Memory, and Cognition [Internet]. 2001 ;27(5):1131 - 1146. Available from: