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Mark McDaniel, (505) 277-2547 Steve Carr, (505) 277-1821

February 27, 2002

UNM PSYCHOLOGY PROFESSOR STUDIES AGING AND MEMORY ILLUSIONS

How do people remember something? To what extent does the aging process affect memory? What are memory illusions and do they become more prevalent with age? How are memory illusions produced and are there strategies that can be used to minimize errors in older adults? Those are some of the questions researchers at the University of New Mexico and Washington University in St. Louis, Mo. hope to find out.

UNM Psychology Department Professor Mark McDaniel and Washington University Professor Henry “Roddy” Roediger are collaborating on an $850,000 grant awarded from the National Institute on Aging (NIA) to study aging and memory illusions.
“Memory illusions are typically defined as remembering events differently from the way they occurred or in the most dramatic case, remembering events that never happened at all,” said McDaniel and Roediger.

McDaniel and Roediger are using three paradigms in subject test groups from college-aged students and older adults (60-80) to specify the reasons that older adults may show exaggerated tendencies for false memories and to identify and test techniques to compensate for age-related exaggerations in memory illusions.

“In the first paradigm subjects are given lists of related words that are derived from a common associate that is omitted from the list,” said McDaniel. “Words like pillow, bed, dream, rest, nap are presented but sleep is not. However, subjects show false recall and recognition of the non-represented, but associatively related word, sleep. It’s expected that the memory illusion is exaggerated for older adults. We also explore techniques for reducing any age-related increases in this type of memory
illusion.

Another paradigm is a misinformation paradigm. Roedeiger and McDaniel are finding that older adults may show more false memory due to the misinformation than younger adults. In the third paradigm subjects perform or imagine events provided in a laboratory context such as ‘roll the toy car,’ ‘tie your shoe.’ When adults repeatedly imagine performing an event, they later recall actually having performed the event. This paradigm is being developed to allow investigation of these memory illusions in older adults.

“We’ve showed in the first months of this grant, that older adults are much more susceptible to this kind of confusion between thinking and doing,” said McDaniel. “In experiments that are ongoing, we have older and younger adults perform a set of actions. We might say ‘roll the car across the desk,’ ‘tie your shoe,’ or ‘comb your hair.’ In addition we had actions people just think about and imagine.

“A couple of weeks later we have the adults come back to the lab and we re-present some of the things they have either imagined or done. What we find is that as you increase the number of imaginings, you’re more likely to say ‘yes, I actually did that’ even though the actions were simply imagined.”

McDaniel says if older adults imagine something only once, in about a third of the cases, two weeks later, they come back to the lab and say ‘I did that.’ If they imagine something twice, over half the time in this experiment, they say ‘I did that’ as opposed to 30 percent for younger adults leading McDaniel and Roediger to believe older adults are more susceptible to this kind of false memory.

“This also has dramatic implications for the real world. Older adults may be taking lots of medications and may be talking about taking medications with other people, they may think about the medication during the day,” said McDaniel. “Our evidence suggests that even in just thinking about the medication older adults may come to think they took the medication. If that’s the case, then they may not take the medication and they under-medicate.”

Another key component to the research hinges on the region of the brain that contributes to memory illusions and which area, either the frontal or hippocampus, might be more at risk with age. To date, it appears the source memory difficulties in older adults tend to be related to the frontal functioning and the binding processes tend to be related to the medial-temporal functioning.

Three possible deficiencies are suggested by different theories that make competing predictions about whether or not older adults will show a greater tendency for illusory memories including source deficiency, retrieval deficiency and binding deficiency.

Source deficiency entails a decline in spontaneous encoding of source information produced by aging. Retrieval deficiency points to self-initiated strategic retrieval processes that decline with age, while binding deficiency is based on memory deficits due to an impaired ability to bind pieces of information together during encoding and storage. According to the binding deficiency idea, source information may be encoded, but older adults do not bind it to the item of information being retrieved, which increases the likelihood of memory illusions.

McDaniel and Roediger are using a battery of neuropsychological tests that index frontal functioning and medial temporal functions to help inform these theoretical views and to derive more detailed predictions about age related arousal of illusory memories.

“First we want to understand the process and then in later years we’ll see what we can do to help older adults overcome the illusions,” said McDaniel. “We hope in the final years, to try and design manipulations or techniques where older adults might overcome these illusions.”

The NIA, one of the 25 institutes and centers of the National Institutes of Health, leads a broad scientific effort to understand the nature of aging and to extend the healthy, active years of life. In 1974, Congress granted authority to form the National Institute on Aging to provide leadership in aging research, training, health information dissemination, and other programs relevant to aging and older people. Subsequent amendments to this legislation designated the NIA as the primary federal agency on Alzheimer’s disease research.

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