A Comparison of Forgetting Rates in Older and Younger Adults

Two experiments investigated the rate of forgetting for recently learned information in older and younger adults. Previous research has been inconclusive, with some studies reporting more rapid forgetting in older adults, whereas others have failed to find any age differences. In several different comparisons, older participants consistently forgot recently studied target words more rapidly than younger participants over a 1 hr retention interval. It appears that age-related difficulties in free recall become more pronounced as the interval between study and test increases, at least under some conditions. Results also confirm a powerful effect of prior testing on episodic memory: Both older and younger participants recalled more words after a delay of 1 hr if they had attempted recall shortly after the study session.     

Episodic intertrial learning of younger and older participants: Effects of age of acquisition

There is clear evidence of a deficit in episodic memory for older adults compared to younger adults. Using an intertrial technique previous research has investigated whether this deficit can be attributed to a decline in encoding or consolidation. On standard memory tests, these two aspects of memory function can be measured by examining the items forgotten or acquired across multiple learning trials. The present study assessed whether age deficits in episodic memory were affected by stimulus characteristics, specifically age of acquisition (AoA). A standard intertrial design was implemented whereby participants studied word lists over several study-test trials. The stimulus characteristics of AoA were manipulated using a pure-list technique. Our findings showed that older adults demonstrate an overall recall deficit which appeared to be a consequence of both an encoding deficit and consolidation weakness. Earlier-acquired words were recalled significantly better than later-acquired words and this was apparently due to both enhanced encoding and consolidation of earlier- over later-acquired words. The key finding is that older adults show a recall advantage for earlier- compared to later-acquired words over the entire experiment to a greater degree than younger adults.     

Reflections of distraction in memory: transfer of previous distraction improves recall in younger and older adults

Three studies explored whether younger and older adults' free recall performance can benefit from prior exposure to distraction that becomes relevant in a memory task. Participants initially read stories that included distracting text. Later, they studied a list of words for free recall, with half of the list consisting of previously distracting words. When the memory task was indirect in its use of distraction (Study 1), only older adults showed transfer, with better recall of previously distracting compared with new words, which increased their recall to match that of younger adults. However, younger adults showed transfer when cued about the relevance of previous distraction both before studying the words (Study 2) and before recalling the words (Study 3) in the memory test. Results suggest that both younger and older adults encode distraction, but younger adults require explicit cueing to use their knowledge of distraction. In contrast, older adults transfer knowledge of distraction in both explicitly cued and indirect memory tasks. Results are discussed in terms of age differences in inhibition and source-constrained retrieval.     

Age-related differences in guessing on free and forced recall tests

This study examined possible age-related differences in recall, guessing, and metacognition on free recall tests and forced recall tests. Participants studied categorised and unrelated word lists and were asked to recall the items under one of the following test conditions: standard free recall, free recall with a penalty for guessing, free recall with no penalty for guessing, or forced recall. The results demonstrated interesting age differences regarding the impact of liberal test instructions (i.e., forced recall and no penalty) relative to more conservative test instructions (i.e., standard free recall and penalty) on memory performance. Specifically, once guessing was controlled, younger adults’ recall of categorised lists varied in accordance with test instructions while older adults’ recall of categorised lists did not differ between conservative and liberal test instructions, presumably because older adults approach standard free recall tests of categorised lists with a greater propensity towards guessing than young adults.     

The effect of forced recall on illusory recollection in younger and older adults

The effect of an initial forced recall test on later recall and recognition tests was examined in younger and older adults. Subjects were presented with categorized word lists and given an initial test under standard cued recall instructions (with a warning against guessing) or forced recall instructions (that required guessing); subjects were later given a cued recall test for the original list items. In 2 experiments, initial forced recall resulted in higher levels of illusory memories on subsequent tests (relative to initial cued recall), especially for older adults. Older adults were more likely to say they remembered rather than knew that forced guesses had occurred in the original study episode. The effect persisted despite a strong warning against making errors in Experiment 2. When a source monitoring test was given, older adults had more difficulty than younger adults in identifying the source of items they had originally produced as guesses. If conditions encourage subjects to guess on a first memory test, they are likely to recollect these guesses as actual memories on later tests. This effect is exaggerated in older adults, probably because of their greater source monitoring difficulties. Both dual process and source monitoring theories provide insight into these findings.     

The effects of aging on selectivity and control in short-term recall

The ability to control encoding and retrieval processing strategically is critical for the efficient use of memory. We examined the ability of younger and older adults to selectively remember words on the basis of their arbitrary point values by using a technique developed by Watkins and Bloom (1999). In the first three experiments, younger subjects recalled more words than did older subjects, but an independent index of recall selectivity showed that older subjects were apparently more successful in selecting higher valued words. However, a fourth experiment showed that this superior selectivity on the part of older adults was attributable to their greater proportional reliance on primary memory recall. Overall, the data suggest that although older adults recall fewer words than do younger adults, they exert as much control over some aspects of encoding.     

Influences of age, performance, and item relatedness on verbatim and gist recall of verb-noun pairs

Age differences in adults' memory for performed actions (e.g., wave hand) are sometimes smaller than age differences in memory for nonperformed phrases. In this study, we examined the conditions under which performance reduces age differences in recall. Younger and older adults performed or read verb-noun phrases that were either related (e.g., actions performed in a kitchen) or unrelated. Performance did not reduce age differences in recall of the exact verbs and nouns used to describe an action, but performance did reduce age differences in memory for the gist of related actions. Older adults especially had difficulty recalling the exact verb used to describe the action. These results suggest that older adults may have better memory for actions than is revealed by tests of verbatim recall. They may remember performing the action but not remember the exact words used to describe the action.     

Comparing the effects of aging and background noise on short-term memory performance

Paired associate recall was tested as a function of serial position for younger and older adults for five word pairs presented aurally in quiet and in noise. In Experiment 1, the addition of noise adversely affected recall in young adults, but only in the early serial positions. Experiments 2 and 3 suggested that the recall of older adults listening to the words in quiet was nearly equivalent to that of younger adults listening in noise. In Experiment 4, we determined the signal-to-noise ratio (S/N) such that, on average, younger and older adults were able to correctly hear the same percentage of words when words were presented one at a time in noise. In Experiment 5, younger adults were tested under this S/N. Compared with older adults from Experiment 3, younger adults in this experiment recalled more words at all serial positions. The results are interpreted as showing that encoding in secondary memory is impaired by aging and noise either as a function of degraded sensory representations, or as a function of reduced processing resources.     

Age-related differences in guessing on free and forced recall tests

This study examined possible age-related differences in recall, guessing, and metacognition on free recall tests and forced recall tests. Participants studied categorised and unrelated word lists and were asked to recall the items under one of the following test conditions: standard free recall, free recall with a penalty for guessing, free recall with no penalty for guessing, or forced recall. The results demonstrated interesting age differences regarding the impact of liberal test instructions (i.e., forced recall and no penalty) relative to more conservative test instructions (i.e., standard free recall and penalty) on memory performance. Specifically, once guessing was controlled, younger adults' recall of categorised lists varied in accordance with test instructions while older adults' recall of categorised lists did not differ between conservative and liberal test instructions, presumably because older adults approach standard free recall tests of categorised lists with a greater propensity towards guessing than young adults.     

Effects of repetition on age differences in associative recognition

The study reported here examined the effect of repetition on age differences in associative recognition using a paradigm designed to encourage recollection at test. Young and older adults studied lists of unrelated word pairs presented one, two, four, or eight times. Test lists contained old (intact) pairs, pairs consisting of old words that had been studied with other partners (rearranged lures), and pairs consisting of two unstudied words (new lures). Participants gave old/new responses and then indicated whether their responses were based on details that they could recollect or on familiarity. Older adults exhibited an ironic effect of repetition—an increase in false alarms on rearranged lures with more study opportunities—whereas young adults did not. Older adults also claimed to recall details of the study episode for rearranged lures whose constituent words were presented more frequently, but this was not true for young adults. Although both young and older adults said that they based correct rejections of rearranged lures on memory for details of the study episode, this effect was stronger for young adults. The observed age differences are consistent with older adults having reduced use of recollection in associative recognition tasks.     

Greater priming for previously distracting information in young than older adults when suppression is ruled out

The use of previously distracting information on memory tests with indirect instructions is usually age-equivalent, while young adults typically show greater explicit memory for such information. This could reflect qualitatively distinct initial processing (encoding) of distracting information by younger and older adults, but could also be caused by greater suppression of such information by younger adults on tasks with indirect instructions. In Experiment 1, young and older adults read stories containing distracting words, which they ignored, before studying a list of words containing previously distracting items for a free recall task. Half the participants were informed of the presence of previously distracting items in the study list prior to recall (direct instruction), and half were not (indirect instruction). Recall of previously distracting words was age-equivalent in the indirect condition, but young adults recalled more distracting words in the direct condition. In Experiment 2, participants performed the continuous identification with recognition task, which captures a measure of perceptual priming and recognition on each trial, and is immune to suppression. Priming and recognition of previously distracting words was greater in younger than older adults, suggesting that the young engage in more successful suppression of previously distracting information on tasks in which its relevance is not overtly signaled.     

False memories in children and adults: age,distinctiveness, and subjective experience

This study investigated developmental trends associated with the Deese/Roediger-McDermott false-memory effect, the role of distinctive information in false-memory formation, and participants' subjective experience of true and false memories. Children (5- and 7-year-olds) and adults studied lists of semantically associated words. Half of the participants studied words alone, and half studied words accompanied by pictures. There were significant age differences in recall (5-year-olds evinced more false memories than did adults) but not in recognition of critical lures. Distinctive information reduced false memory for all age groups. Younger children provided with distinctive information, and older children and adults regardless of whether they viewed distinctive information, expressed higher levels of confidence in true than in false memories. Source attributions did not significantly differ between true and false memories. Implications for theories of false memory and memory development are discussed.     

Age-related deficits in free recall: The role of rehearsal

Age-related deficits have been consistently observed in free recall. Recent accounts of episodic memory suggest that these deficits could result from differential patterns of rehearsal. In the present study, 20 young and 20 older adults (mean ages 21 and 72 years, respectively) were presented with lists of 20 words for immediate free recall using the overt rehearsal methodology. The young outperformed the older adults at all serial positions. There were significant age-related differences in the patterns of overt rehearsals: Young adults rehearsed a greater number of different words than did older adults, they rehearsed words to more recent serial positions, and their rehearsals were more widely distributed throughout the list. Consistent with a recency-based account of episodic memory, age deficits in free recall are largely attributable to age differences in the recency, frequency, and distribution of rehearsals.     

Priming guesses on a forced-recall test

The forced-recall paradigm requires participants to fill all spaces on the memory test even if they cannot remember all the list words. In the present study, the authors used that paradigm to examine the influence of implicit memory on guessing--when participants fill remaining spaces after they cannot remember list items. They measured explicit memory as the percentage of targets that participants designated as remembered from the list and implicit memory as the percentage of targets they wrote but did not designate as remembered (beyond chance level). The authors examined implicit memory on guessing with forced recall (Experiment 1), forced cued recall with younger and older adults (Experiment 2), and forced free and cued recall under a depth-of-processing manipulation (Experiment 3). They conclude that implicit memory influences guesses of targets in the forced-recall paradigm.     

The effects of sad mood on memory in older adults: a test of the mood congruence effect

Mood congruence effects have long been studied in younger adults, but not in older adults. Socioemotional selectivity theory (SST) suggests that mood congruence could operate differently in older adults. One hundred and nineteen younger and 78 older adults were randomly assigned to sad or neutral mood inductions, using combined Velten and music induction procedures. Results indicated that during sad mood induction both older and younger adults showed enhanced recall of sad words on delayed word list recall task and in autobiographical memory. However, only older adults displayed mood congruence effects on lexical ambiguity and lower recall of positive words in the word list task. Results provided partial support for developmental effects on mood congruence derived from SST.     

Use of relational and item-specific information in remembering by older and younger adults

The applicability to older adults of predictions from the integrated memory model, that optimal memory results from concurrent availability of relational and item-specific information, was assessed. In Experiment 1, older adults (M = 69 years) encoded related or unrelated words using rating, sorting, or both tasks. Using both tasks produced better recall than either separate task. Rating facilitated recall for related items, but sorting did not facilitate unrelated items. In Experiment 2, younger (M = 20) and older (M = 74) adults sorted or rated lists comprising categories of varying sizes. Young adults' free recall conformed to predictions, but older adults again showed facilitation mainly from rating larger categories. The stronger effects for younger adults imply that specific combinations of encoding and retrieval manipulations and materials must be considered in predicting older adults' performance.     

Self-generation amplifies the errorless learning effect in healthy older adults when transfer appropriate processing conditions are met

ABSTRACT Errorless learning improves memory for older adults by providing individuals with correct information from the onset, thereby minimizing the misleading influence of errors. Our previous research demonstrated that self-generation enhanced the errorless learning effect among older adults in cued recall when encoding encouraged processing of cue-target relationships, suggesting that transfer appropriate processing is necessary for this interactive effect ( Lubinsky, Rich, & Anderson, 2009 , Journal of the International Neuropsychological Society, 15, 704). The current study further tests this notion by investigating whether the interaction of errorless learning and self-generated learning is observed in free recall when study conditions foster encoding of inter-item associations. Healthy older adult participants studied related or unrelated words (manipulated between-subjects) under four within-subjects learning conditions representing the crossing of errorless/errorful learning and self-generated/experimenter-provided information. As predicted, self-generation enhanced the errorless learning advantage in free recall for related word lists but not unrelated word lists. The results are discussed in relation to the transfer appropriate processing view of generation effects.     

Remembering Words Never Presented: False Memory Effects in Dementia of the Alzheimer Type

Thirty-five young adults, 35 older adults and 29 individuals with dementia of the Alzheimer’s type studied lists of semantically related words (e.g., thread, pin, sewing) that converged on a non-presented lure (needle). Compared to the young adults, older adults remembered (recall and recognition tests) fewer studied items but falsely remembered more non-presented lures. Memory for studied items was lower in the DAT group compared to normal elders. The DAT group did recall some non-presented lures, although unlike the older adults, recall of non-presented lures was not elevated compared to veridical memory. Similar to the normal elders, the DAT group showed increased susceptibility to false recognition of non-presented lures. Susceptibility to false recognition did not vary as a function of disease severity.     

Adult Age Differences in Memory for Verbs and Nouns

Younger and older adults were asked to remember noun pairs (e.g., head – cap), verb pairs (e.g., bounce – throw), and verb-noun pairs (e.g., break – stick). For half of the pairs, participants used imagined objects and performed an action or series of related actions for each pair. For the other half of the pairs, participants read but did not perform the pairs. Free recall and cued recall tests revealed that age differences in memory for both performed and nonperformed items were larger for verbs than for nouns. The recall advantage of nouns over verbs was larger for older than for younger adults. Verbs are hypothesized to be more difficult for older adults to remember because they are more and less specific than nouns and because it is more difficult to integrate verbs with other words than to integrate nouns with other words.