Adult age differences in function concept learning

Function concept learning and knowledge use was explored across adulthood. During training older and younger adults predicted an amount of physiological arousal produced as a negative and positive function of a chemical substance. Knowledge use was evaluated with two transfer conditions requiring a switch between contextual contingencies: a relationship inversion, predicting the chemical amount given the physiological arousal, and a change from graphic based to text based stimuli. Older adults were impaired in applying the negative slope concept. However, there was no relative deficit in switching between the negative and positive function slopes or inverting the learned relationship. Our results suggest that age-related differences in relational reasoning tasks vary not only with processing efficiency, but also task related conceptual knowledge.     

Adult age differences in self-regulated learning from reading sentences

We examined age differences in the heuristic used to allocate effort in learning information from sentences. Younger and older adults read and reread sentences varying in propositional density for recall, making judgments of learning before producing recall. The allocation of effort in rereading items that were less well learned on the first reading was optimized for sentences of intermediate complexity, especially for older adults. These data support a model of self-regulated learning in which readers reduce the discrepancy between current and optimal states of learning. However, self-regulation, which may be procedure based or rely on an implicit representation of the current state of learning, may be particularly efficient for older adults within a region of proximal learning.     

Adult age differences in working memory

Active and passive measures of short-term memory over a large segment of the adult life span were compared. Two hundred twenty-eight volunteers, aged 30 to 99 years, performed the digit span forward and backward task, the Peterson-Peterson task, and a new working memory task in which active manipulation of information is emphasized. Age differences were slight for passive tasks. For the working memory task, significant declines were found between the ages of 60 to 69 and 70+ years. It is suggested that the age differences may be due to a decrease in the flexibility with which processing changes are made.     

Adult age differences in short-term forgetting

Two experiments are reported in which young and old adults performed in a Brown-Peterson task. In the first experiment young adults recalled with greater accuracy than old adults and the difference between age groups was greater in delayed than in immediate recall. Performance varied inversely with interpolated task difficulty in the delayed recall condition, but this effect did not interact with age. In the second experiment an attempt was made to equate immediate recall performances of old and young adults to determine if age differences in the rate of forgetting are independent of age differences in registration. Each participant was pre-tested to determine the number of stimulus repetitions needed to achieve a minimum of 83% correct in immediate serial recall of 6-letter sequences. The number of repetitions an individual required in pre-testing was then used in a subsequent Brown-Peterson task. No significant age differences in delayed recall were obtained when immediate recall differences were minimized by differential repetition of to-be-remembered sequences. The results of these experiments suggest that age differences in forgetting rates arise from age-related differences in encoding and storage.     

Adult age differences in working memory

Two experiments were conducted to determine whether adult age differences in working memory should be attributed to less efficient processing, a smaller working memory storage capacity, or both. In Experiment 1, young, middle-age, and older adults solved three addition problems before giving the answers to any. Older adults added as well as young and middle-age adults but showed a more pronounced serial position curve across the three problem positions. In Experiment 2, young and older adults constructed linear orderings (e.g., ABCD) from pairwise information presented in sentences (e.g., BC). Manipulations involving processing (e.g., type of sentence) did not interact with age differences, but those involving storage capacity (e.g., ordering length) did. All main effects and interactions support the hypothesis of a smaller storage capacity but do not rule out some processing deficit in older adults.     

Adult age differences in task switching

Age differences in 2 components of task-set switching speed were investigated in 118 adults aged 20 to 80 years using task-set homogeneous (e.g., AAAA ...) and task-set heterogeneous (e.g., AABBAABB ... ) blocks. General switch costs were defined as latency differences between heterogeneous and homogeneous blocks. whereas specific switch costs were defined as differences between switch and nonswitch trials within heterogeneous blocks. Both types of costs generalized over verbal, figural, and numeric stimulus materials; were more highly correlated to fluid than to crystallized abilities; and were not eliminated after 6 sessions of practice, indicating that they reflect basic and domain-general aspects of cognitive control. Most important, age-associated increments in costs were significantly greater for general than for specific switch costs, suggesting that the ability to efficiently maintain and coordinate 2 alternating task sets in working memory instead of 1 is more negatively affected by advancing age than the ability to execute the task switch itself.     

Adult age differences in categorization and multiple-cue judgment

We often need to infer unknown properties of objects from observable ones, just like detectives must infer guilt from observable clues and behavior. But how do inferential processes change with age? We examined young and older adults' reliance on rule-based and similarity-based processes in an inference task that can be considered either a categorization or a multiple-cue judgment task, depending on the nature of the criterion (binary vs. continuous). Both older and young adults relied on rule-based processes in the multiple-cue judgment task. In the categorization task, however, the majority of older adults relied on rule-based processes while young adults preferred similarity-based processes. Moreover, older adults who relied on rule-based processes performed poorly compared with young adults who relied on the same process, suggesting that aging is associated with deficits in applying rule-based processes.     

Adult age differences in attentional selectivity and capacity

Abstract

This paper reviews empirical research on adult age differences in the use of attention during visual search and classification tasks. This research suggests that the selective aspect of attention, in the sense of the ability to discriminate relevant and irrelevant information, is relatively resistant to age-related change. The capacity aspect of attention, in the sense of the limited processing resources that underlie task performance, appears to undergo age-related decline. Questions remain, however, regarding whether capacity-reduction explanations of age differences in cognitive performance have any advantages over explanations based on task complexity. Recent analyses of ageing and attention emphasise the potential contribution of formal models of cognitive performance.     

Adult age differences in temporal and item memory

Three experiments tested whether the relationship between age differences in temporal and item memory depends on the degree to which the item memory measure relies on memory for context. The authors predicted a stronger relationship of temporal memory to free recall than to recognition memory. Results showed that age differences in temporal memory could be eliminated after controlling for free recall but not recognition memory performance. Under some conditions recognition memory accounted for a significant portion of age-related variance in temporal memory. These results challenge past research that has interpreted age differences in temporal and item memory as independent and suggest that a generalized decline in context memory may underlie reduced performance in older adults on all types of memory tests.     

Adult age differences in letter-level and word-level processing

Older and young adults' letter detection and lexical decision performance were examined as word frequency varied to determine whether there were age differences in word recognition. Allen and Madden (1989) found that older adults' pattern of reaction time (RT) across word frequency categories was different from young adults' pattern for a letter detection task. In this study, for both letter detection and lexical decision tasks, older adults exhibited a monotonically decreasing RT function as word frequency increased. However, young adults exhibited a nonmonotonic RT function across word frequency for the letter detection task but a monotonically decreasing RT function as word frequency increased for the lexical decision task. An expanded parallel input serial analysis model of word processing was hypothesized.     

Adult age differences in memory for name-face associations: The effects of intentional and incidental learning

Previous studies have indicated that older adults have a special deficit in the encoding and retrieval of associations. The current study assessed this deficit using ecologically valid name-face pairs. In two experiments, younger and older participants learned a series of name-face pairs under intentional and incidental learning instructions, respectively, and were then tested for their recognition of the faces, the names, and the associations between the names and faces. Under incidental encoding conditions older adults' performance was uniformly lower than younger adults in all three tests, indicating age-related impairments in episodic memory representations. An age-related deficit specific to associations was found under intentional but not under incidental learning conditions, highlighting the importance of strategic associative processes and their decline in older adults. Separate analyses of hits and false alarms indicate that older adults' associative deficit originated from high false alarm rates in the associative test. Older adults' high false alarm rates potentially reflect their reduced ability to recollect the study-phase name-face pairs in the presence of intact familiarity with individual names and faces.     

Adult age differences in the rate of learning serial patterns: evidence from direct and indirect tests.

Subjects performed a serial reaction time task (adopted from Nissen & Bullemer, 1987) that contained a repeating pattern of spatial locations. In Experiment 1, following 20 repetitions of a 10- or 16-element pattern, reaction time was equally disrupted for both younger and older people when the sequence became random. In Experiment 2, the response times for subjects encountering the 10-element pattern were compared with those of subjects encountering a random sequence. These response time functions diverged at the same point in training for the 2 age groups. Thus, on this indirect measure of response time facilitation, both experiments revealed age similarity in the rate of pattern learning. In contrast, on a subsequent direct test of pattern learning that required prediction, the younger people earned a higher percentage correct score than the older in both experiments. Age-related dissociations between direct and indirect measures of learning and comparisons with memory-impaired populations are discussed.     

Adult age differences in the perceptual span during reading

Following up on research suggesting an age-related reduction in the rightward extent of the perceptual span during reading (Rayner, Castelhano, & Yang, 2009), we compared old and young adults in an N + 2-boundary paradigm in which a nonword preview of word N + 2 or word N + 2 itself is replaced by the target word once the eyes cross an invisible boundary located after word N. The intermediate word N + 1 was always three letters long. Gaze durations on word N + 2 were significantly shorter for identical than nonword N + 2 preview both for young and for old adults, with no significant difference in this preview benefit. Young adults, however, did modulate their gaze duration on word N more strongly than old adults in response to the difficulty of the parafoveal word N + 1. Taken together, the results suggest a dissociation of preview benefit and parafoveal-on-foveal effect. Results are discussed in terms of age-related decline in resilience towards distributed processing while simultaneously preserving the ability to integrate parafoveal information into foveal processing. As such, the present results relate to proposals of regulatory compensation strategies older adults use to secure an overall reading speed very similar to that of young adults.     

Motivational incentives modulate age differences in visual perception

This study examined whether motivational incentives modulate age-related perceptual deficits. Younger and older adults performed a perceptual discrimination task in which bicolored stimuli had to be classified according to their dominating color. The valent color was associated with either a positive or negative payoff, whereas the neutral color was not associated with a payoff. Effects of incentives on perceptual efficiency and response bias were estimated using the diffusion model (Ratcliff, 1978). Perception of neutral stimuli showed age-related decline, whereas perception of valent stimuli, both positive and negative, showed no age difference. This finding is interpreted in terms of preserved top-down control over the allocation of perceptual processing resources in healthy aging.     

Adult age differences in autobiographical reasoning in narratives

Two studies examined age differences in autobiographical reasoning within narratives about personal experiences. In Study 1 (n=63), people completed brief interviews about turning points and crises in their lives. Older participants were more likely to narrate crises in ways that connected the experience to the speaker's sense of self, that is, to show autobiographical reasoning. This increase was primarily evident in young adulthood and midlife. In Study 2 (n=115), adults provided written narratives about heterogeneous autobiographical experiences. Age was associated with linear increases in the likelihood of autobiographical reasoning. The results are discussed in terms of narrative approaches to self-development across the life span.     

Adult age differences in goal activation and goal maintenance

According to the goal-neglect hypothesis of age-related decrements in cognitive control advocated in this paper, such decrements can be usefully and parsimoniously attributed to a reduced capacity for goal selection and goal maintenance in working memory. A selective review of research findings on age-related differences in exogenous and endogenous control of visual attention and eye movements and on performance in the task-switching paradigm serves to illustrate and clarify this hypothesis. The relative merits and scope of the hypothesis are examined within a broader theoretical perspective on the organisation of the domain of executive functions.     

Adult age differences in attention to semantic context

In three experiments age differences in attention to semantic context were examined. The performance of younger adults (ages 18-29 years) and older adults (ages 60-79 years) on a semantic priming task indicated that both age groups could use information regarding the probability that a prime and target would be related to flexibly anticipate the target category given the prime word (Experiment 1). The timing by which target expectancies were reflected in reaction time performance was delayed for older adults as compared to younger adults, but only when the target was expected to be semantically unrelated to the prime word (Experiment 2). When the target and prime were expected to be semantically related, the time course of priming effects was similar for younger and older adults (Experiment 3). Together the findings indicate that older adults are able to use semantic context and the probability of stimulus relatedness to anticipate target information. Although aging may be associated with a delay in the timing by which controlled expectancies are expressed, these findings argue against an age-related decline in the ability to represent contextual information.