Age-related similarities and differences in cognitive and neural processing revealed by task-related microstate analysis.

We explored neural processing differences associated with aging across four cognitive functions. In addition to ERP analysis, we included task-related microstate analyses, which identified stable states of neural activity across the scalp over time, to explore whole-head neural activation differences. Younger and older adults (YA, OA) completed face perception (N170), word-pair judgment (N400), visual oddball (P3), and flanker (ERN) tasks. Age-related effects differed across tasks. Despite age-related delayed latencies, N170 ERP and microstate analyses indicated no age-related differences in amplitudes or microstates. However, age-related condition differences were found for P3 and N00 amplitudes and scalp topographies: smaller condition differences were found for in OAs as well as broader centroparietal scalp distributions. Age group comparisons for the ERN revealed similar focal frontocentral activation loci, but differential activation patterns. Our findings of differential age effects across tasks are most consistent with the STAC-r framework which proposes that age-related effects differ depending on the resources available and the kinds of processing and cognitive load required of various tasks.

Electrophysiological concomitants of pupillary synchrony.

Pupillary synchrony or contagion is the automatic unconscious mimicry of pupil dilation in dyadic interactions. This experiment explored electrophysiological event-related potential (ERP) concomitants of pupillary synchrony. Artificial pupils (black dots) were superimposed on either partial faces (eyes, nose, brow) or random textures. Observers were asked to judge dot size (large, medium, or small). There was clear evidence of pupillary synchrony with observer pupil dilation greater to large dots than to small or medium dots. The pupillary synchrony increased in magnitude throughout the trial and was found both with faces and with textures. When the stimuli were partial faces with artificial pupils (dots), there was ERP activity related to target dot size in the period at P250 and P3. A face specific N170 was also found. When the stimuli were random textures with dots, there was ERP activity at P1 and in the interval from 140 to 200 ms post-stimulus onset. The use of ERP with pupillometry revealed results for faces that were consistent with a social explanation of pupillary synchrony whereas results for textures were consistent with a local luminance explanation.

Secular Changes in Masters Swimming Performances: A 40-Year Follow Up.

Archival records of US Masters Swimming performances were examined for changes between 1981 and 2021. Both national records and top 10 swimmers were used. Substantial secular changes were found averaging 0.52%/yr, with women improving more than men and with improvements in national records greater than in the top 10. Performances by women in 2021 were at parity (national records) or near parity (top 10) with men in 1981. The results indicate that secular effects must be considered along with longitudinal age-related changes and cross-sectional cohort effects in interpreting age differences in physiological function.

Information interference and loss in a dual task situation: Task 1, choice reaction time; Task 2, unspeeded recall.

The extraction and maintenance of second task information was explored in four dual task experiments. A variant of the psychological refractory period procedure was used with the first task, a speeded choice reaction to a tone and the second task, the unspeeded recall of letter triplets. Prior research had shown that recall accuracy dropped as the stimulus-onset asynchrony (SOA) decreased and task overlap increased. This could be due to interference with extracting perceptual information or to loss of the information while awaiting central resources. All four experiments showed evidence of interference, with the accuracy of recall for the first letter recalled relatively unaffected by SOA but with accuracy for later letters dropping as SOA decreased. Two of the experiments showed evidence for loss of second task information, with accuracy lower on trials with longer first task reaction times. The two other experiments showed loss of information when either the response complexity of Task 1 or the perceptual encoding difficulty was increased, increasing the processing time. The observed interference was attributed to slowed extraction of perceptual information. The observed loss was consistent with the encoded information being held in a fragile temporary store, susceptible to loss until consolidated into short-term memory. The evidence showed that the interference and the loss were independent processes.

Equivalent pupillary mimicry in younger and older adults.

Pupillary contagion is a form of autonomic mimicry in which faces with dilated pupils elicit larger pupils in observers whereas faces with constricted pupils elicit smaller pupils. Autonomic reactivity may be fundamental to higher order social processes, yet older adults may be less likely to register other's autonomic signals. We explored pupillary contagion in younger and older adult observers. We presented younger and older observers with partial-face photographs of women with the pupils manipulated to be small, medium, or large. The faces were either young (20s) or old (70s). There were two tasks: To judge the model's age and to judge which pupil was larger. In the pupil judgment task, the magnitude of response was lower in older adults than in younger adults, but both younger and older observers showed equivalent pupillary contagion. In the age judgment task, which did not draw attention to the pupils, we found no evidence of pupillary contagion in either age-group. Registration of the autonomic signal of pupil dilation does not appear to be impaired in older adults. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Attentional effects of hand proximity occur later in older adults: Evidence from event-related potentials.

Research with young adults has shown hand proximity biases attention both early (by the time stimuli are categorized as relevant for action) and later, selectively for goal-relevant-stimuli. We examined age-related changes in this multisensory integration of vision and proprioception by comparing behavior and event-related potentials (ERPs) between younger and older adults. In a visual detection task, the hand was placed near or kept far from target and nontarget stimuli matched for frequency and visual features. Although a behavioral hand proximity effect-faster response times for stimuli appearing near the hand-was found for both age groups, a proportionately larger effect was found for younger adults. ERPs revealed age-related differences in the time course of the hand's effect on visual processing. Younger adults showed selective increases in contralateral N1 and parietal P3 amplitudes for targets near the hand, but older adults only showed hand effects at the P3 which were accompanied by concurrent neural activity in bilateral frontal regions. This neural pattern suggests that compared with younger adults, older adults may produce the behavioral hand proximity effect by integrating hand position and visual inputs relying more on later, task-related, frontal attentional mechanisms and less on early, posterior, multisensory integration. (PsycINFO Database Record

Backward compatibility effects in younger and older adults.

In many dual-task situations, responses to the second of two tasks are slowed when the time between tasks is short. The response-selection bottleneck model of dual-task performance accounts for this phenomenon by assuming that central processing of the second task is blocked by a bottleneck until central processing of Task 1 is complete. This assumption could be called into question if it could be demonstrated that the response to Task 2 affected the central processing of Task 1, a backward response compatibility effect. Such effects are well-established in younger adults. Backward compatibility effects in older (as well as younger) adults were explored in two experiments. The first experiment found clear backward response compatibility effects for younger adults but no evidence of them for older adults. The second experiment explored backward stimulus compatibility and found similar effects in both younger and older adults. Evidence possibly consistent with some pre-bottleneck processing of Task 2 central stages also was found in the second experiment in both age groups. For younger adults, the results provide further evidence falsifying the claim of an immutable response selection bottleneck. For older adults, the evidence suggested that Task 2 affects Task 1 when there is stimulus compatibility but not when there is response compatibility.

Ideomotor-compatible tasks partially escape dual-task interference in both young and elderly adults.

Under most circumstances, it is not possible to carry out central processing for 2 tasks at the same time; effectively there is a bottleneck. Nevertheless, in 2 experiments it is demonstrated here that both younger and older adults are able to partially bypass the bottleneck in a psychological refractory period procedure, even without extensive training, when the 2nd of the 2 tasks is a saccade or a body tilt in the direction of rotation of a visual stimulus. Consistent with earlier research, the findings showed that younger adults can bypass when the second task has ideomotor-compatible stimuli and responses. Most strikingly, they demonstrated that bypass can also occur in older adults. Overall, the findings are inconsistent with any categorical claim that younger adults can bypass the dual-task bottleneck whereas older adults cannot. The construct of ideomotor-compatible tasks may comprise 2 quite different classes of experimental procedures.

An Age-Related Dissociation of Short-Term Memory for Facial Identity and Facial Emotional Expression.

BACKGROUND: Memory for both facial emotional expression and facial identity was explored in younger and older adults in 3 experiments using a delayed match-to-sample procedure. METHOD: Memory sets of 1, 2, or 3 faces were presented, which were followed by a probe after a 3-s retention interval. RESULTS: There was very little difference between younger and older adults in memory for emotional expressions, but memory for identity was substantially impaired in the older adults. DISCUSSION: Possible explanations for spared memory for emotional expressions include socioemotional selectivity theory as well as the existence of overlapping yet distinct brain networks for processing of different emotions.

Attention's grasp: early and late hand proximity effects on visual evoked potentials.

Behavioral studies suggest that visual attention is biased toward stimuli in the region of space near the palm of the hand, but it is unclear whether this effect is universal or selective for goal/task-related stimuli. We examined event-related potentials (ERPs) using a visual detection task in which the hand was placed near or kept far from target and non-target stimuli that were matched for frequency and visual features to avoid confounding factors. Focusing on attention-sensitive ERP components, we found that P3 (350-450 ms) amplitudes were increased for Hand Near conditions for targets only, demonstrating a selective effect consistent with the P3's cross-modal and task-relevance influences. An N1 variant implicated in visuo-tactile integration (central Nd1; 120-190 ms) showed similar target-specific effects. P1 (80-110 ms) effects for target stimuli were also apparent, but may have applied to non-targets as well, which would be consistent with the P1's association with early, pre-categorical increases in sensory gain. Collectively, these findings suggest that by the time stimuli are categorized as relevant/irrelevant for action, the proprioceptive effects of the hand on visual attention are selective for goal/task-related stimuli. At the same time, hand proximity appears to bias attention early, starting with a facilitation of processing for perhaps any visual stimuli near the hand, and continuing with enhancements that are selective to those stimuli categorized as task-relevant.

Age and method variance in measures of speed and working memory.

Ten measures of speed of processing were administered to 157 individuals, aged 18 to 89 years. The 10 measures comprised five pairs, each of which had a paper-and-pencil and a computer, reaction time (RT) based version of the same measure. Three measures of working memory span were also administered. Two structural equation models were fit to the speed data, one with a single latent variable, speed, and another, nested-factor model in which there were also latent variables for the two methods of measurement. The model with the method latent variables provided a better fit. Age was more strongly related to the method latent variables than to the general speed latent variable. Adding the working memory measures showed that there was also shared variance in those measures beyond the general latent variable, also related to age. The results show that any single measure of speed includes variance due to speed but also to the method of measurement. Use of a latent variable approach to speed is recommended.

Assigned value improves memory of proper names.

Names are more difficult to remember than other personal information such as occupations. The current research examined the influence of assigned point value on memory and metamemory judgements for names and occupations to determine whether incentive can improve recall of proper names. In Experiment 1 participants studied face-name and face-occupation pairs assigned 1 or 10 points, made judgements of learning, and were given a cued recall test. High-value names were recalled more often than low-value names. However, recall of occupations was not influenced by value. In Experiment 2 meaningless nonwords were used for both names and occupations. The name difficulty disappeared, and value influenced recall of both names and occupations. Thus value similarly influenced names and occupations when meaningfulness was held constant. In Experiment 3 participants were required to use overt rote rehearsal for all items. Value did not boost recall of high-value names, suggesting that differential processing could not be implemented to improve memory. Thus incentives may improve memory for proper names by motivating people to engage in selective rehearsal and effortful elaborative processing.

Novice motor performance: better not to verbalize.

Offline verbalization about a new motor experience is often assumed to positively influence subsequent performance. Here, we evaluated this presumed positive influence and whether it originates from declarative or from procedural knowledge using the explicit/implicit motor-learning paradigm. To this end, 80 nongolfers learned to perform a golf-putting task with high error rates (i.e., explicit motor learning), and thus relied on declarative knowledge, or low error rates (i.e., implicit motor learning), and thus relied on procedural knowledge. Afterward, they either put their memories of the previous motor experience into words or completed an irrelevant verbal task. Finally, they performed the putting task again. Verbalization did not improve novice motor performance: Putting was impaired, overall, and especially so for high-error learners. We conclude that declarative knowledge is altered by verbalization, whereas procedural knowledge is not.

Electrodermal responses to sources of dual-task interference.

There is a response selection bottleneck that is responsible for dual-task interference. How the response selection bottleneck operates was addressed in three dual-task experiments. The overlap between two tasks (as indexed by the stimulus onset asynchrony [SOA]) was systematically manipulated, and both reaction time and electrodermal activity were measured. In addition, each experiment also manipulated some aspect of the difficulty of either task. Both increasing task overlap by reducing SOA and increasing the difficulty of either task lengthened reaction times. Electrodermal response was strongly affected by task difficulty but was only weakly affected by SOA, and in a different manner from reaction time. A fourth experiment found that the subjectively perceived difficulty of a dual-task trial was affected both by task difficulty and by SOA, but in different ways than electrodermal activity. Overall, the results were not consistent with a response selection bottleneck that involves processes of voluntary, executive attention. Instead, the results converge with findings from neural network modeling to suggest that the delay of one task while another is being processed reflects the operation of a routing mechanism that can process only one stream of information for action at a time and of a passive, structural store that temporarily holds information for the delayed task. The results suggest that conventional blocked or event-related neuroimaging designs may be inadequate to identify the mechanism of operation of the response selection bottleneck.

Age effects shrink when motor learning is predominantly supported by nondeclarative, automatic memory processes: evidence from golf putting.

Can motor learning be equivalent in younger and older adults? To address this question, 48 younger (M = 23.5 years) and 48 older (M = 65.0 years) participants learned to perform a golf-putting task in two different motor learning situations: one that resulted in infrequent errors or one that resulted in frequent errors. The results demonstrated that infrequent-error learning predominantly relied on nondeclarative, automatic memory processes whereas frequent-error learning predominantly relied on declarative, effortful memory processes: After learning, infrequent-error learners verbalized fewer strategies than frequent-error learners; at transfer, a concurrent, attention-demanding secondary task (tone counting) left motor performance of infrequent-error learners unaffected but impaired that of frequent-error learners. The results showed age-equivalent motor performance in infrequent-error learning but age deficits in frequent-error learning. Motor performance of frequent-error learners required more attention with age, as evidenced by an age deficit on the attention-demanding secondary task. The disappearance of age effects when nondeclarative, automatic memory processes predominated suggests that these processes are preserved with age and are available even early in motor learning.

Input, retention, and output factors affecting adult age differences in visuospatial short-term memory.

OBJECTIVES: The sources of age differences in short-term memory for spatial locations were explored in 2 experiments that examined factors related to input, to maintenance, and to output. METHOD: In each experiment, 4 dots were presented briefly, followed after a retention interval by a probe dot, which was judged to either match or not match one of the 4 memory-set dots. RESULTS AND DISCUSSION: Results showed that poorer performance by older adults could be attributed independently to reduced visual acuity, to less effective use of rehearsal strategies, and to differences in response biases.

Dual-task processing in younger and older adults: similarities and differences revealed by fMRI.

fMRI was used to explore age differences in the neural substrate of dual-task processing. Brain activations when there was a 100 ms SOA between tasks, and task overlap was high, were contrasted with activations when there was a 1000 ms SOA, and first task processing was largely complete before the second task began. Younger adults (M=21 yrs) showed activation in dorsolateral prefrontal cortex and in parietal areas as well as in ventral medial frontal cortex and sub-lobar areas. Activations in older adults (M=71 yrs) did not differ significantly from younger adults except for higher activations in occipital and polar prefrontal cortex. The results were well fit by a model with two networks managing dual-task interference, a medial prefrontal network that detects changes in the stimulus situation and maps them to associated changes in the valence of response mappings and a lateral frontal-parietal network that initiates and carries out the shift from one task to the other. The additional activations in older adults as a group and the correlations of individual differences in activation with performance were consistent with recruitment within each of these networks. Alternative explanations such as hemispheric asymmetry reduction and reactive rather than proactive processing in older adults were not supported.

A demonstration of dual-task performance without interference in some older adults.

Highly efficient dual-task processing is demonstrated when reaction time to each of two tasks does not differ between the dual-task situation and the single-task situation. This has been demonstrated reliably in younger adults; nevertheless, the two extant studies of extensive dual-task training did not find evidence for it in any elderly adult. The origins of age-related differences after training were explored in a study in which the stimuli for the two tasks were perfectly redundant although two distinct responses were required. The dual-task situation thus greatly reduced the demands of stimulus categorization while still requiring two response selections and two response executions. After only limited training 8 of 8 younger adults and 5 of 8 older adults showed performance consistent with highly efficient processing. Three older adults failed to show this even after 12 training sessions. The results implicate stimulus categorization more than response selection as an important locus of inefficient dual-task processing, particularly for older adults.

Success and failure at dual-task coordination by younger and older adults.

Dual-task processing was explored in younger and older adults in 2 experiments that used a tone discrimination and a letter discrimination task. To encourage parallel processing if that was possible, the authors presented the stimuli for the 2 tasks simultaneously, and participants were instructed to withhold their responses until both were ready. The authors found no evidence for parallel processing and no evidence that the management of central processing of dual tasks is qualitatively different in older adults than it is in younger adults. When one response was verbal and the other manual, the 2 responses closely coincided. When both responses were manual, the authors did find that the first response was not delayed enough to coincide with the 2nd and that this underestimation was greater in older adults.

Can practice overcome age-related differences in the psychological refractory period effect?

Can dual-task practice remove age-related differences in the psychological refractory period (PRP) effect? To answer this question, younger and older individuals practiced 7 blocks of a PRP design, in which Task 1 (T1) required a vocal response to an auditory stimulus and Task 2 (T2) required a manual response to a visual stimulus (Experiment 1). The results showed that practice did not reduce, but rather increased, age-related differences in PRP interference. Using the trained individuals, the introduction of a less complex new T1 (Experiment 2) or a less complex new T2 (Experiment 3) with the task previously practiced reduced the PRP interference but only in older adults. The authors propose that older adults suffer from a large task-switch cost that is more sensitive to task complexity than to the amount of practice.