Age differences in what is viewed and remembered in complex conjunction search

Older and younger adults searched arrays of 12 unique real-world photographs for a specified object (e.g., a yellow drill) among distractors (e.g., yellow telephone, red drill, and green door). Eye-tracking data from 24 of 48 participants in each age group showed generally similar search patterns for the younger and older adults but there were some interesting differences. Older adults processed all the items in the arrays more slowly than the younger adults (e.g., they had longer fixation durations, gaze durations, and total times), but this difference was exaggerated for target items. We also found that older and younger adults differed in the sequence in which objects were searched, with younger adults fixating the target objects earlier in the trial than older adults. Despite the relatively longer fixation times on the targets (in comparison to the distractors) for older adults, a surprise visual recognition test revealed a sizeable age deficit for target memory but, importantly, no age differences for distractor memory.     

Ageing and feature binding in visual working memory: The role of presentation time

A large body of research has clearly demonstrated that healthy ageing is accompanied by an associative memory deficit. Older adults exhibit disproportionately poor performance on memory tasks requiring the retention of associations between items (e.g., pairs of unrelated words). In contrast to this robust deficit, older adults’ ability to form and temporarily hold bound representations of an object's surface features, such as colour and shape, appears to be relatively well preserved. However, the findings of one set of experiments suggest that older adults may struggle to form temporary bound representations in visual working memory when given more time to study objects. However, these findings were based on between-participant comparisons across experimental paradigms. The present study directly assesses the role of presentation time in the ability of younger and older adults to bind shape and colour in visual working memory using a within-participant design. We report new evidence that giving older adults longer to study memory objects does not differentially affect their immediate memory for feature combinations relative to individual features. This is in line with a growing body of research suggesting that there is no age-related impairment in immediate memory for colour-shape binding.     

Aging and memory for expected and unexpected objects in real-world settings.

Adult age differences in the consistency effect were examined in 3 experiments. The consistency effect refers to items inconsistent with expectations being better remembered than items consistent with expectations. Younger and older adults walked into an office room and viewed objects that varied in their consistency with expectation. Immediate and delayed recognition tests on item information (i.e., distractors were defined by their semantic identity) revealed that both age groups recognized unexpected items better than expected items. However, when recognition of token information was requested (i.e., distractors were defined by their physical appearance), younger adults, in contrast to older adults, exhibited consistency effects. Also, under divided attention, young adults revealed the same pattern of data as did elderly adults under full attention. The results are discussed in terms of capacity-related differences in distinctive encoding.     

Incidental and intentional visual memory: What memories are and are not affected by encoding tasks?

Prior research into the impact of encoding tasks on visual memory (Castelhano & Henderson, 2005) indicated that incidental and intentional encoding tasks led to similar memory performance. The current study investigated whether different encoding tasks impacted visual memories equally for all types of objects in a conjunction search (e.g., targets, colour distractors, object category distractors, or distractors unrelated to the target). In sequences of pictures, participants searched for prespecified targets (e.g., green apple; Experiment 1), memorized all objects (Experiment 2), searched for specified targets while memorizing all objects (Experiment 3), searched for postidentified targets (Experiment 4), or memorized all objects with one object prespecified (Experiment 5). Encoding task significantly improved visual memory for targets and led to worse memory for unrelated distractors, but did not influence visual memory of distractors that were related to the target's colour or object category. The differential influence of encoding task indicates that the relative importance of the object both positively and negatively influences the memory retained.     

Influence of recollection and plausibility on age-related deficits in associative memory

Age-related declines in associative memory are proposed to result from deficits in older adults’ ability to recollect the past. The present experiment investigated the ability of older adults to compensate for deficits in recollecting the past by using plausibility. Participants studied a list of word pairs that shared category or rhyme relations. To measure the processes used during the recognition memory test, participants provided self-reported explanations for their memory judgements. Older adults relied primarily on plausibility, and the younger adults relied on both plausibility and recollection. Older adults experienced both positive and negative consequences as a result of using a knowledge-based strategy to compensate for their decreased ability to recollect the past. Specifically, they were just as capable as younger adults at recognising previously studied items and correctly rejecting distractors that were inconsistent with the rule provided at study. However, they falsely recognised distractors that were consistent with that rule more often than younger adults.     

Influence of recollection and plausibility on age-related deficits in associative memory

Age-related declines in associative memory are proposed to result from deficits in older adults' ability to recollect the past. The present experiment investigated the ability of older adults to compensate for deficits in recollecting the past by using plausibility. Participants studied a list of word pairs that shared category or rhyme relations. To measure the processes used during the recognition memory test, participants provided self-reported explanations for their memory judgements. Older adults relied primarily on plausibility, and the younger adults relied on both plausibility and recollection. Older adults experienced both positive and negative consequences as a result of using a knowledge-based strategy to compensate for their decreased ability to recollect the past. Specifically, they were just as capable as younger adults at recognising previously studied items and correctly rejecting distractors that were inconsistent with the rule provided at study. However, they falsely recognised distractors that were consistent with that rule more often than younger adults.     

Aging, memory and visual search

Potential age-related differences in the memory processes that underlie visual search are examined in the present study. Using a dynamic, gaze-contingent search paradigm developed to assess memory for previously examined distractors, older adults demonstrated no memory deficit. Surprisingly, older adults made fewer refixations compared to their younger counterparts, indicating better memory for previously inspected objects. This improved memory was not the result of a speed-accuracy trade-off or larger Inhibition-of-Return effects for older than for younger adults. Additional analyses suggested that older adults may derive their benefit from finer spatial encoding of search items. These findings suggest that some of the memory processes that support visual search are relatively age invariant.     

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.     

Age effects on social cognition: faces tell a different story

The authors administered social cognition tasks to younger and older adults to investigate age-related differences in social and emotional processing. Although slower, older adults were as accurate as younger adults in identifying the emotional valence (i.e., positive, negative, or neutral) of facial expressions. However, the age difference in reaction time was largest for negative faces. Older adults were significantly less accurate at identifying specific facial expressions of fear and sadness. No age differences specific to social function were found on tasks of self-reference, identifying emotional words, or theory of mind. Performance on the social tasks in older adults was independent of performance on general cognitive tasks (e.g., working memory) but was related to personality traits and emotional awareness. Older adults also showed more intercorrelations among the social tasks than did the younger adults. These findings suggest that age differences in social cognition are limited to the processing of facial emotion. Nevertheless, with age there appears to be increasing reliance on a common resource to perform social tasks, but one that is not shared with other cognitive domains.     

Age differences in the distractor-ratio effect as a function of contrast level

Latencies (RT) and eye movement measures were used to examine the effects of age and contrast on the distractor-ratio effect (DRE) in visual search. Younger and older adults performed a contrast x orientation conjunction search task where the ratios of white to black distractors and luminance contrast levels were varied. The distractor-ratio manipulation had similar effects for older and younger adults on both RT and the number of fixations required to find the target. Both measures were largely independent of distractor ratio on target-present trials, while both RTs and the fixation number increased with the number of items sharing the target's contrast polarity on target-absent trials. A more detailed analysis of eye movements suggested that younger adults were a bit more adept at attending to the smaller set of distractors, which presumably facilitated both overt and covert search. Generalized slowing can account for the age differences in RT, but the fixation number data speak to another mechanism, perhaps increased cautiousness on the part of the elderly when signal strength is low.     

Asymmetric aging effects on semantic and phonological processes: naming in the picture-word interference task

In 2 experiments, participants named pictures while ignoring auditory word distractors. For pictures with homophone names (e.g., ball), distractors semantically related to the nondepicted meaning (e.g., prom) facilitated naming by top-down phonological connections for young but not for older adults. Slowing from unrelated distractors and facilitation from phonologically related distractors were age invariant except in distractors that were both semantically and phonologically related. Only distractors semantically related to the picture interfered more for older than younger adults. These results ar einconsistent with age-linked deficits in inhibition of irrelevant information from either internal or external sources. Rather, aging affects priming transmission in a connectionist network with asymmetric effects on semantic and phonological connections involved in comprehension and production, respectively.     

Spatial updating of multiple targets: Comparison of younger and older adults

When walking without vision, people mentally keep track of the directions and distances of previously viewed objects, a process called spatial updating. The current experiment indicates that while people across a large age range are able to update multiple targets in memory without perceptual support, aging negatively affects accuracy, precision, and decision time. Participants (20 to 80 years of age) viewed one, three, or six targets (colored lights) on the floor of a dimly lit room. Then, without vision, they walked to a target designated by color, either directly or indirectly (via a forward turning point). The younger adults’ final stopping points were both accurate (near target) and precise (narrowly dispersed), but updating performance did degrade slightly with the number of targets. Older adults’ performance was consistently worse than the younger group, but the lack of interaction between age and memory load indicates that the effect of age on performance was not further exacerbated by a greater number of targets. The number of targets also significantly increased the latency required to turn toward the designated target for both age groups. Taken together, results extend previous work showing impressive updating performance by younger adults, with novel findings showing that older adults manifest small but consistent degradation of updating performance of multitarget arrays.     

Age Differences in the Distractor-Ratio Effect as a Function of Contrast Level

ABSTRACT

Latencies (RT) and eye movement measures were used to examine the effects of age and contrast on the distractor-ratio effect (DRE) in visual search. Younger and older adults performed a contrast × orientation conjunction search task where the ratios of white to black distractors and luminance contrast levels were varied. The distractor-ratio manipulation had similar effects for older and younger adults on both RT and the number of fixations required to find the target. Both measures were largely independent of distractor ratio on target-present trials, while both RTs and the fixation number increased with the number of items sharing the target's contrast polarity on target-absent trials. A more detailed analysis of eye movements suggested that younger adults were a bit more adept at attending to the smaller set of distractors, which presumably facilitated both overt and covert search. Generalized slowing can account for the age differences in RT, but the fixation number data speak to another mechanism, perhaps increased cautiousness on the part of the elderly when signal strength is low.     

Variations in processing resources and resistance to false memories in younger and older adults

The influence of available processing resources on the resistance to false memories (FMs) for lists of semantically related items associated with a non-presented critical lure was examined in younger and older adults. Reducing the available resources at encoding in younger adults (Experiments 1 and 2) led to a performance similar to that of older adults (i.e., higher rates of FMs in addition to reduced rates of correct recall). However, increasing the available resources (Experiments 2 and 3) led to improvements in the rates of correct recall in both age groups and decreased the probability of FMs in younger adults, although warnings had to be added in older adults to obtain similar effects on FMs. Parallel influences on a post-recall test asking participants to report items that they had thought of but did not recall were also found. The influence of available cognitive resources for memory accuracy is also discussed with respect to activation-monitoring (e.g., McDermott & Watson, 2001) and fuzzy-trace (e.g., Brainerd & Reyna, 2002) accounts of age-related increased in false memories.     

Collaboration reduces the frequency of false memories in older and younger adults

Older (mean age = 74.23) and younger (mean age = 33.50) participants recalled items from 6 briefly exposed household scenes either alone or with their spouses. Collaborative recall was compared with the pooled, nonredundant recall of spouses remembering alone (nominal groups). The authors examined hits, self-generated false memories, and false memories produced by another person's (actually a computer program's) misleading recollections. Older adults reported fewer hits and more self-generated false memories than younger adults. Relative to nominal groups, older and younger collaborating groups reported fewer hits and fewer self-generated false memories. Collaboration also reduced older people's computer-initiated false memories. The memory conversations in the collaborative groups were analyzed for evidence that collaboration inhibits the production of errors and/or promotes quality control processes that detect and eliminate errors. Only older adults inhibited the production of wrong answers, but both age groups eliminated errors during their discussions. The partners played an important role in helping rememberers discard false memories in older and younger couples. The results support the use of collaboration to reduce false recall in both younger and older adults.     

Self-Regulated Learning in Younger and Older Adults: Does Aging Affect Metacognitive Control?

ABSTRACT

Two experiments examined whether younger and older adults' self-regulated study (item selection and study time) conformed to the region of proximal learning (RPL) model when studying normatively easy, medium, and difficult vocabulary pairs. Experiment 2 manipulated the value of recalling different pairs and provided learning goals for words recalled and points earned. Younger and older adults in both experiments selected items for study in an easy-to-difficult order, indicating the RPL model applies to older adults' self-regulated study. Individuals allocated more time to difficult items, but prioritized easier items when given less time or point values favoring difficult items. Older adults studied more items for longer but realized lower recall than did younger adults. Older adults' lower memory self-efficacy and perceived control correlated with their greater item restudy and avoidance of difficult items with high point values. Results are discussed in terms of RPL and agenda-based regulation models.     

Stronger evidence for own-age effects in memory for older as compared to younger adults

Three studies examined whether younger and older adults better recall information associated with their own than information related to another age group. All studies compared young and older adults with respect to incidental memory for previously presented stimuli (Studies 1 and 2: everyday objects; Study 3: vacation advertisements) that had been randomly paired with an age-related cue (e.g., photo of a young or an old person; the word "young" or "old"). All three studies found the expected interaction of participants' age and age-associated information. Studies 1 and 2 showed that the memory bias for information arbitrarily associated with one's own as compared to another age group was significant for older adults only. However, when age-relevance was introduced in a context of equal importance to younger and older adults (information about vacations paired either with pictures of young or older adults), the memory bias for one's own age group was clearly present for both younger and older adults (Study 3).     

Hiding valuables: A questionnaire study of mnemonically risky behavior

A survey investigated incidences where individuals intentionally hid objects but later forgot the item's location. Surveys from 111 younger and 99 older adults yielded the following prototypical scenario: the person hid the valuable 1 year ago to prevent theft, and waited 1 month before an initial 30-minute search, which included looking in dresser drawers plus 1.5 other locations. The person made three additional searches (total searches = 4) for the missing valuable over a 2 week period. Three-quarters of the hidden valuables were eventually found (usually by accident) about 1 month after hiding the object. About half of the time, the person had already searched the hiding area. Older adults typically hid jewellery from thieves, while younger adults hid money from friends and relatives. Older adults searched more often for longer periods of time for the hidden object, and took longer to eventually find the object, compared with younger adults.     

Stronger evidence for own-age effects in memory for older as compared to younger adults

Three studies examined whether younger and older adults better recall information associated with their own than information related to another age group. All studies compared young and older adults with respect to incidental memory for previously presented stimuli (Studies 1 and 2: everyday objects; Study 3: vacation advertisements) that had been randomly paired with an age-related cue (e.g., photo of a young or an old person; the word “young” or “old”). All three studies found the expected interaction of participants’ age and age-associated information. Studies 1 and 2 showed that the memory bias for information arbitrarily associated with one's own as compared to another age group was significant for older adults only. However, when age-relevance was introduced in a context of equal importance to younger and older adults (information about vacations paired either with pictures of young or older adults), the memory bias for one's own age group was clearly present for both younger and older adults (Study 3).