Effects of repetition and response deadline on associative recognition in young and older adults

That's the man who did it, or was it a woman? Actor similarity and binding errors in event memory

Mistakes in eyewitness identification frequently occur when incorrect associations are made between a familiar person and the actions of another person. The present research demonstrates that actors do not need to be similar in appearance for such conjunction errors to occur. The actors can, in fact, be very different in appearance, even of different sexes. Participants attempted to remember a series of brief everyday events, each involving an actor performing an action. Increases in actor similarity led to increases in conjunction errors in which participants incorrectly associated a familiar actor with a familiar action that was actually performed by someone else, but conjunction errors frequently occurred even when the familiar actor was of a different sex than the original actor, arguing against the hypothesis that these conjunction errors are due solely to mistaken identity.

Memory systems do not divide on consciousness: Reinterpreting memory in terms of activation and binding

There is a popular hypothesis that performance on implicit and explicit memory tasks reflects 2 distinct memory systems. Explicit memory is said to store those experiences that can be consciously recollected, and implicit memory is said to store experiences and affect subsequent behavior but to be unavailable to conscious awareness. Although this division based on awareness is a useful taxonomy for memory tasks, the authors review the evidence that the unconscious character of implicit memory does not necessitate that it be treated as a separate system of human memory. They also argue that some implicit and explicit memory tasks share the same memory representations and that the important distinction is whether the task (implicit or explicit) requires the formation of a new association. The authors review and critique dissociations from the behavioral, amnesia, and neuroimaging literatures that have been advanced in support of separate explicit and implicit memory systems by highlighting contradictory evidence and by illustrating how the data can be accounted for using a simple computational memory model that assumes the same memory representation for those disparate tasks.

Working memory capacity for spoken sentences decreases with adult ageing: recall of fewer but not smaller chunks in older adults

Previous studies show that older adults have poorer immediate recall for language but the reason is unknown. Older adults may recall fewer chunks from working memory, or may have difficulty binding words together to form multi-unit chunks. We examined these two hypotheses by presenting four types of spoken sentences for immediate free recall, differing in the number and length of chunks per trial: four short, simple sentences; eight such sentences; four compound sentences, each incorporating two meaningful, short sentences; and four random word lists, each under a sentence-like intonation. Older adults recalled words from (accessed) fewer clauses than young adults, but there was no ageing deficit in the degree of completion of clauses that were accessed. An age-related decline in working memory capacity measured in chunks appears to account for deficits in memory for spoken language.

Differential effects of normal aging on memory for odor-place and object-place associations

Odor-place and object-place associative memory were compared in healthy older (over the age of 65) and young (18 to 25 years of age) adults. Twelve spatial locations were defined on a tabletop board. Either six odors or six objects were presented one at a time and each was paired with a location on the board. The participant then was presented with each stimulus individually and asked to place it in its paired location. Older adults showed impaired odor-place associative memory but unimpaired object-place memory compared to young adults. Item recognition memory for the individual stimuli or locations used on the associative memory task was similar in both groups. The results suggest that odor-place associative memory is particularly affected by age-related brain changes.

Adult age differences in binding actors and actions in memory for events

Three experiments provide evidence for an age-related deficit in the binding of actors with their actions. Young and older adults were tested on their memory for a series of events, each involving an actor performing a simple action. Older adults had greater difficulty than did young adults at discriminating old events from novel conjunctions of familiar actors and actions, even when the two groups were equated on memory for each of those features in isolation by using a longer retention interval for young adults. These results are consistent with an age-related associative deficit linked to declines in hippocampal and prefrontal cortical functioning. They further provide evidence that age differences in source monitoring are not limited to speech acts but, rather, generalize to more complex actions. Finally, they provide evidence for age differences in susceptibility to conjunction memory errors, stemming from decreased reliance on recollection and increased reliance on familiarity with increased age. Example videos may be downloaded from www.psychonomic.org/archive.

Effects of age on contextually mediated associations in paired associate learning

Older and young adults learned single-function lists of paired associates with no contextual overlap (e.g., J-K, L-M) and double-function lists of paired associates consisting of chains of pairs (e.g., A-B, B-C). Although young adults outperformed older adults on both pair types, there was a robust Pair Type x Age interaction. Evidence from intrusion analyses shows that older adults performed better than would be expected on the contextually overlapping double-function pairs because they were less subject to response competition for the double-function pairs. Young adults made a larger proportion of backward and remote intrusions to double-function probes than did older adults. Thus, group differences in both correct-recall probabilities and intrusion analysis suggest that backward and transitive associations are sensitive to aging. The results are discussed within the theoretical framework of the temporal context model and the hypothesis that older adults are impaired at forming new item-context associations.

Recollection and familiarity in amnestic mild cognitive impairment: a global decline in recognition memory

Despite memory failures being a central feature of amnestic mild cognitive impairment (a-MCI), there is limited research into the nature of the memory impairment associated with this condition. A further understanding could lead to refinement of criteria needed to qualify for this designation and aid in prediction of who will progress to development of clinical Alzheimer's disease. Dual process models posit that recognition memory is supported by the dissociable processes of recollection and familiarity. The present study sought to evaluate recognition memory in a-MCI in the framework of the dual process model. Patients with a-MCI and age- and education-matched controls were tested on three memory paradigms. Two paradigms were modifications of the process-dissociation procedure in which recollection required either memory of word-pair associations (associative) or the font color of words at study (featural). A final paradigm utilized the task-dissociation methodology comparing performance for item and visual spatial source memory. All three tasks revealed that familiarity was impaired to at least the same extent as recollection. As familiarity is thought to be spared in normal aging, its measurement may provide a relatively specific marker for the early pathological changes of Alzheimer's disease.

Modeling the effects of verbal and nonverbal pair strength on associative recognition

Operations that improve the accuracy of associative recognition can do so in qualitatively different ways. Increasing repetitions and study time increases hit rates but has small effects on false alarm rates, and the specific patterns of false alarms are dependent on the stimuli (e.g., pairs of words, pseudowords, faces, or Chinese characters). In contrast, manipulating the type of stimuli that make up pairs produces a robust mirror effect: The hit rate is greater, and the false alarm rate is lower, for better recognized stimuli. To explain these findings, a model of single-item recognition is extended to associative recognition. Within this dual-process framework, the present results suggest that words are encoded more extensively than nonverbal stimuli and that recognition of frequently encountered stimuli (words and faces) is more likely to be based on recollection than is recognition of uncommon stimuli (pseudowords and Chinese characters).

Inadvertent plagiarism in young and older adults: the role of working memory capacity in reducing memory errors

Two experiments examined inadvertent plagiarism in young and older adults. Young and older adults took turns generating category exemplars in small groups, and after a short retention interval recall was tested and subjects were asked to generate new exemplars (i.e., exemplars not initially generated). When asked to generate new exemplars, older adults were more likely to repeat exemplars that had been generated earlier by others (i.e., generate-new plagiarism). When asked to recall the exemplars they had generated earlier, older adults were more likely to claim that they had generated exemplars that had been generated by others (i.e., recall-own plagiarism), and were also more likely to falsely recall exemplars that had not been generated at all. There were no age differences in confidence for items that were plagiarized on the generate-new task. Hierarchical regression analyses indicated that age differences in generate-new plagiarism and false recall were entirely mediated by measures of episodic recall and working memory capacity. We conclude that inadvertent plagiarism errors result from the failure of systematic decision processes, and that controlled attention is important for avoiding memory errors.

Paying attention to binding: Further studies assessing the role of reduced attentional resources in the associative deficit of older adults

The present experiments investigated whether the observed associative deficit in older adults' episodic memory is mediated by a reduction of attentional resources. Using a dual-task procedure, younger and older participants studied lists of word pairs either under full attention or while performing a concurrent task. Both experiments showed that dividing attention did not cause a greater impairment to memory for associations than to memory for items in either age group. Furthermore, an analysis of concurrent task performance revealed that older adults' attentional costs for both learning and binding items were not larger than for learning items alone, relative to younger adults. These data provide support for a multicausal interpretation of older adults' memory deficits in which common, depleted attentional resources may be a mechanism that reduces memory for components of an episode in both older and younger adults under divided attention at encoding. In addition, older adults have a unique deficit in memory for the associations between the components, which does not seem to be resource dependent.

Age-related differences in immediate serial recall: dissociating chunk formation and capacity

We assessed the contribution of two hypothesized mechanisms to impaired memory performance of older adults in an immediate serial recall task: decreased temporary information storage in a capacity-limited mechanism, such as the focus of attention, and a deficit in binding together different components into cohesive chunks. Using a method in which paired associations between words were taught at varying levels to allow an identification of multiword chunks (Cowan, Chen, & Rouder, 2004), we found that older adults recalled considerably fewer chunks and, on average, smaller chunks than did young adults. Their performance was fairly well simulated by dividing attention in younger adults, unlike what has been found for long-term associative learning. Paired-associate knowledge may be used in an implicit manner in serial recall, given that younger adults under divided attention and older adults use it well despite the relatively small chunk capacities displayed by these groups.

Aging selectively impairs recollection in recognition memory for pictures: evidence from modeling and receiver operating characteristic curves

Young and older adults were tested on recognition memory for pictures. The Yonelinas high threshold (YHT) model, a formal implementation of 2-process theory, fit the response distribution data of both young and older adults significantly better than a normal unequal variance signal-detection model. Consistent with this finding, nonlinear z-transformed receiver operating characteristic curves were obtained for both groups. Estimates of recollection from the YHT model were significantly higher for young than for older adults. This deficit was not a consequence of a general decline in memory; older adults showed comparable overall accuracy and in fact a nonsignificant increase in their familiarity scores. Implications of these results for theories of recognition memory and the mnemonic deficit associated with aging are discussed.

Effects of repetition and response deadline on item recognition in young and older adults

In the present study, we examined the joint effects of aging, repetition, and response deadline in a plurality discrimination task. Young and older adults studied lists of unrelated singular and plural nouns, with half presented once (weak items) and half presented five times (strong items). Test lists contained old (same) nouns, plurality-reversed nouns (changed lures), and unstudied nouns (new lures), and the participants were asked to respond old only to same items. In Experiment 1, the participants were tested with both short and long deadlines. In Experiment 2, the tests were unpaced. In both experiments, repetition increased hit rates for young and older adults. Young adults tested with a long deadline or no deadline showed invariant (Experiment 1) or reduced (Experiment 2) false alarms to changed lures when the nouns were studied more often. Young adults tested with a short deadline and older adults tested with both long and short deadlines had increased false alarm rates for strong changed lures; without time pressure to respond, older adults did not have a significant increase in false alarms for changed lures. Implications of these results for theories of cognitive aging are explored.

Do distractors interfere with memory for study pairs in associative recognition?

In an associative recognition task, distractors generally consist of a rearrangement of the items composing the study pairs. This makes it possible that processing the distractors generates retroactive interference on memory for the study pairs. In Experiment 1, we explored this possibility in a yes/no recognition test concerning previously learned arbitrary associations between visual symbols and auditory syllables. Rearranged pairs had a deleterious impact on the accuracy and the speed of responses to related correct pairs. This effect did not vary as a function of the number of training blocks, and furthermore, in Experiment 2, the same effect was observed for overlearned small multiplication facts. These results suggest that exposure to potentially confounding information generates interference even if this information is known to be incorrect. Some implications are outlined, especially with regard to the widespread use of multiple-choice tests in knowledge evaluation.

Dual-process models of associative recognition in young and older adults: evidence from receiver operating characteristics

In 3 experiments, young and older adults studied lists of unrelated word pairs and were given confidence-rated item and associative recognition tests. Several different models of recognition were fit to the confidence-rating data using techniques described by S. Macho (2002, 2004). Concordant with previous findings, item recognition data were best fit by an unequal-variance signal detection theory model for both young and older adults. For both age groups, associative recognition performance was best explained by models incorporating both recollection and familiarity components. Examination of parameter estimates supported the conclusion that recollection is reduced in old age, but inferences about age differences in familiarity were highly model dependent. Implications for dual-process models of memory in old age are discussed.

Conjunction errors in recognition memory: modality-free errors for older adults but not for young adults

A dual-process theory of memory was applied to processes in normal aging, with a focus on recognition errors in the feature-conjunction paradigm (i.e., false recognition of blackbird after studying parent words blackmail and/or jailbird). Study repetition was manipulated so that some parent words occurred once and others occurred three times. Age-related differences on hit scores occurred for two experiments. The results for feature and conjunction conditions showed repetition effects but no age-related differences when participants were uninformed of the lures (Experiment 1). However, age-related differences emerged when the retrieval of modality source information created a way to evade conjunction errors (Experiment 2). In the second experiment, study repetition decreased errors for the young adults but increased errors for the older adults, and young adults were better able than older adults to avoid conjunction errors when the parent words had been repeated. For older adults, the conjunction errors were modality-free. The results provide additional evidence that older adults experience difficulty in recollecting aspects of a study experience, and the results from groups of young adults required to respond quickly on the tests provide converging evidence for this conclusion.