Interactive effects of working memory and trial history on Stroop interference in cognitively healthy aging

Executive functions involved in thought suppression: An attempt to integrate research in two paradigms

There are two main thought suppression research paradigms: the White Bear and Think/No-Think paradigms. In Think/No-Think research, thought suppression is effective and is considered to be mediated by prepotent response inhibition. Conversely, in White Bear studies, thought suppression is counterproductive and appears to engage resistance to proactive interference. However, findings regarding the involvement of these executive functions in each task are mixed. In the current study, two thought suppression procedures were compared. Using Friedman and Miyake's inhibitory functions model (2004) it was investigated whether the differences between thought suppression tasks can be explained by involvement of different executive functions. The results showed that the suppression phases of both procedures were correlated, but the outcomes of suppression were unrelated. There was no evidence supporting the involvement of the examined executive functions in either thought suppression task. Commonalities and discrepancies of the two tasks are discussed along with their external validity.

Age differences in inhibitory and working memory functioning: limited evidence of system interactions

Debate persists regarding the nature of age-related deficits in inhibition, and whether inhibitory functioning depends on working memory systems. The current research aimed to measure age-related differences in inhibition and working memory, characterize the relationship between inhibitory functions and working memory performance, and determine how these relationships are affected by age. Toward these ends, we measured performance on a range of established paradigms in 60 young adults (18-30 years) and 60 older adults (60-88 years). Our findings support age-related increases in reflexive inhibition (based on the fixation offset effect and inhibition of return) and age-related decrements in volitional inhibition (based on several paradigms: antisaccade, Stroop, flanker, and Simon). This evidence of stronger reflexive inhibition combined with weaker volitional inhibition suggests that age-related deterioration of cortical structures may allow subcortical structures to operate less controlled. Regarding working memory, older adults had lower backward digit scores and lower forward and backward spatial scores. However, of the 32 analyses (16 in each age group) that tested for dependence of inhibitory functioning on working memory functioning, only one (in young adults) indicated that inhibition performance significantly depended on working memory performance. These results indicate that inhibition and working memory function largely independently in both age groups, and age-related working memory difficulties cannot account for age-related declines in inhibitory control.

Age-related differences in food-specific inhibitory control: Electrophysiological and behavioral evidence in healthy aging

The number of older adults in the United States is estimated to nearly double from 52 million to 95 million by 2060. Approximately 80-85% of older adults are diagnosed with a chronic health condition. Many of these chronic health conditions are influenced by diet and physical activity, suggesting improved diet and eating behaviors could improve health-related outcomes. One factor that might improve dietary habits in older adults is food-related inhibitory control. We tested whether food-related inhibitory control, as measured via behavioral data (response time, accuracy) and scalp-recorded event-related potentials (ERP; N2 and P3 components), differed between younger and older adults over age 55. Fifty-nine older adults (31 females [52.5%], M_age = 64, SD_age = 7.5) and 114 younger adults (82 females [71.9%], M_age = 20.8) completed two go/no-go tasks, one inhibiting to high-calorie stimuli and one inhibiting to low-calorie stimuli, while electroencephalogram (EEG) data were recorded. Older adults had slower overall response times than younger adults, but this was not specific to either food task. There was not a significant difference in accuracy between younger and older adults, but both groups' accuracy and response times were significantly better during the high-calorie task than the low-calorie task. For both the N2 and P3 ERP components, younger adults had larger no-go ERP amplitudes than older adults, but this effect was not food-specific, reflecting overall generalized lower inhibitory control processing in older adults. P3 amplitude for the younger adults demonstrated a specific food-related effect (greater P3 amplitude for high-calorie no-go than low-calorie no-go) that was not present for older adults. Findings support previous research demonstrating age-related differences in inhibitory control though those differences may not be specific to inhibiting towards food.

Neuropsychological Correlates of Changes in Driving Behavior Among Clinically Healthy Older Adults

OBJECTIVES

To determine the extent to which cognitive domain scores moderate change in driving behavior in cognitively healthy older adults using naturalistic (Global Positioning System-based) driving outcomes and to compare against self-reported outcomes using an established driving questionnaire.

METHODS

We analyzed longitudinal naturalistic driving behavior from a sample (N = 161, 45% female, mean age = 74.7 years, mean education = 16.5 years) of cognitively healthy, nondemented older adults. Composite driving variables were formed that indexed "driving space" and "driving performance." All participants completed a baseline comprehensive cognitive assessment that measured multiple domains as well as an annual self-reported driving outcomes questionnaire.

RESULTS

Across an average of 24 months of naturalistic driving, our results showed that attentional control, broadly defined as the ability to focus on relevant aspects of the environment and ignore distracting or competing information as measured behaviorally with tasks such as the Stroop color naming test, moderated change in driving space scores over time. Specifically, individuals with lower attentional control scores drove fewer trips per month, drove less at night, visited fewer unique locations, and drove in smaller spaces than those with higher attentional control scores. No cognitive domain predicted driving performance such as hard braking or sudden acceleration.

DISCUSSION

Attentional control is a key moderator of change over time in driving space but not driving performance in older adults. We speculate on mechanisms that may relate attentional control ability to modifications of driving behaviors.

Proportional Changes in Cognitive Subdomains During Normal Brain Aging

Background: Neuroscience lacks a reliable method of screening the early stages of dementia. Objective: To improve the diagnostics of age-related cognitive functions by developing insight into the proportionality of age-related changes in cognitive subdomains. Materials and Methods: We composed a battery of psychophysiological tests and collected an open-access psychophysiological outcomes of brain atrophy (POBA) dataset by testing individuals without dementia. To extend the utility of machine learning (ML) classification in cognitive studies, we proposed estimates of the disproportional changes in cognitive functions: an index of simple reaction time to decision-making time (ISD), ISD with the accuracy performance (ISDA), and an index of performance in simple and complex visual-motor reaction with account for accuracy (ISCA). Studying the distribution of the values of the indices over age allowed us to verify whether diverse cognitive functions decline equally throughout life or there is a divergence in age-related cognitive changes. Results: Unsupervised ML clustering shows that the optimal number of homogeneous age groups is four. The sample is segregated into the following age-groups: Adolescents ∈ [0, 20), Young adults ∈ [20, 40), Midlife adults ∈ [40, 60) and Older adults ≥60 year of age. For ISD, ISDA, and ISCA values, only the median of the Adolescents group is different from that of the other three age-groups sharing a similar distribution pattern (p > 0.01). After neurodevelopment and maturation, the indices preserve almost constant values with a slight trend toward functional decline. The reaction to a moving object (RMO) test results (RMO_mean) follow another tendency. The Midlife adults group's median significantly differs from the remaining three age subsamples (p < 0.01). No general trend in age-related changes of this dependent variable is observed. For all the data (ISD, ISDA, ISCA, and RMO_mean), Levene's test reveals no significant changes of the variances in age-groups (p > 0.05). Homoscedasticity also supports our assumption about a linear dependency between the observed features and age. Conclusion: In healthy brain aging, there are proportional age-related changes in the time estimates of information processing speed and inhibitory control in task switching. Future studies should test patients with dementia to determine whether the changes of the aforementioned indicators follow different patterns.

Some further clarifications on age-related differences in the Stroop task: New evidence from the two-to-one Stroop paradigm

Previous studies (Augustinova et al., Psychonomic Bulletin & Review, 25(2), 767-774, 2018; Li & Bosman, Aging, Neuropsychology, and Cognition, 3(4), 272-284, 1996) have shown that the larger Stroop effects reported in older adults is specifically due to age-related differences in the magnitude of response - and not semantic - conflict, both of which are thought to contribute to overall Stroop interference. However, the most recent contribution to the issue of the unitary versus composite nature of the Stroop effect argues that semantic conflict has not been clearly dissociated from response conflict in these or any other past Stroop studies, meaning that the very existence of semantic conflict is at present uncertain. To distinguish clearly between the two types of conflict, the present study employed the two-to-one Stroop paradigm with a color-neutral word baseline. This addition made it possible to isolate a contribution of semantic conflict that was independent of both response conflict and Stroop facilitation. Therefore, this study provides the first unambiguous empirical demonstration of the composite nature of Stroop interference - as originally claimed by multi-stage models of Stroop interference. This permitted the further observation of significantly higher levels of semantic conflict in older adults, whereas the level of response conflict in the present study remained unaffected by healthy aging - a finding that directly contrasts with previous studies employing alternative measures of response and semantic conflict. Two qualitatively different explanations of this apparent divergence across studies are discussed.

Cognition in Motion: Evidence for Intact Action Control With Healthy Aging

Objectives

Healthy aging is associated with impairments in motor functioning. Such functioning is not limited to the physical execution of actions, but also involves cognitive processes that allow for goal-directed behavior. The present study examined whether aging affects 2 of such cognitive components that control motor functioning, namely action planning and action adaptation, and whether age effects are associated across components.

Method

A group of 103 participants aged 18–82 years performed 2 tasks that have previously been linked to action planning and adaptation, respectively.

Results

Despite observations that aging was associated with slower and less accurate responses, Bayesian models showed evidence indicating that older age was not associated with poorer action planning and conflict adaptation.

Discussion

These findings challenge the view that healthy aging is associated with a general deficit in motor functioning and suggest that some cognitive aspects of motor control may be relatively spared.

Stroop switching card test: brief screening of executive functions across the lifespan

This study aimed to: (1) propose a novel version of the Stroop switching test, namely the Stroop Switching Card Test (SSCT), to assess the overall efficiency of executive functions (EF) and its underlying cognitive processes (conflict resolution and conflict adaptation); (2) examine the utility of the SSCT in the assessment of EF in different age groups (age range 15-75 years), compare its results with standard neuropsychological tests (SNT), and (3) examine the contribution of both the processing speed and cognitive reserve on the performance of all used tests. The SSCT showed more sensitivity to detect subtle executive dysfunction in the middle age (~50 years). Going further, the SSCT revealed a progressive decline in conflict adaptation over two life periods. The first period of decline started at ~50 years and the second at~ 65 years. The processing speed and cognitive reserve had a prominent role in our results, notably in SSCT.

Response initiation and inhibition and the relationship with fluid intelligence across the adult lifespan

Background

Cognitive processes associated with frontal lobe functioning are often termed “executive functions.” Two such processes are initiation and inhibition or the starting and stopping of responses. It has recently been claimed dysfunction of executive abilities can be explained by a single measure of fluid intelligence. Here, we test this claim, specifically for the executive abilities of response initiation and inhibition, across the healthy lifespan.

Method

In a cohort of 336 healthy adults (18–89 years), initiation and inhibition were assessed with the Hayling test, Stroop test, and phonemic and semantic verbal fluency. All participants also completed a measure of fluid intelligence. The relationship between fluid intelligence and executive measures was explored across the lifespan using a continuous approach. Mediation models were computed to assess whether age-related decline across the four initiation/inhibition tasks could be fully explained by a single measure of fluid intelligence.

Results

Age was negatively correlated with response initiation/inhibition and fluid intelligence. The mediation analyses identified only partial mediation of fluid intelligence for age and Hayling performance. By contrast, fluid intelligence did not mediate performance on the Stroop test or phonemic and semantic verbal fluency.

Conclusions

Response initiation/inhibition are not able to be explained by fluid intelligence. The results support a multifactorial theory of executive functions and provide evidence for the inclusion of multiple specific executive measures in a thorough neuropsychological assessment of age-related cognitive decline.

Attentional Reorientation and Inhibition Adjustment in a Verbal Stroop Task: A Lifespan Approach to Interference and Sequential Congruency Effect

Several parameters influence the interference effect elicited in a Stroop task, especially contextual information. Contextual effects in the Stroop paradigms are known as the Gratton or Sequential congruency effect (SCE). This research aims at isolating two processes contributing to the SCE in a Stroop paradigm, namely attentional reorientation from the color to the word and vice-versa, as well as inhibition (engagement/disengagement from one trial to the next one). To this end, in Study 1 subprocesses of the SCE were isolated. Specifically, attentional reorientation and inhibition were segregated by submitting young adults to a discrete verbal Stroop task including neutral trials. In Study 2, the same procedure was applied to 124 participants aged from 10 to 80 years old to analyze how interference, SCE, and the aforementioned decomposition of attention and inhibition change across the lifespan. In both studies, the Gratton effect was only partially replicated, while both attentional reorientation and inhibition effects were observed, supporting the idea that these two processes contribute to SCE on top of conflict monitoring and of other processes highlighted in different theories (contingency learning, feature integration, and repetition expectancy). Finally, the classical age-related evolution was replicated in Study 2 on raw interference scores, but no age effect was observed when processing speed was taken into account, nor on the isolated attentional reorientation and inhibition processes, which is in line with the hypothesis of stability of the inhibition processes over age.

Additive Effects of Item-Specific and Congruency Sequence Effects in the Vocal Stroop Task

There is a growing interest in assessing how cognitive processes fluidly adjust across trials within a task. Dynamic adjustments of control are typically measured using the congruency sequence effect (CSE), which refers to the reduction in interference following an incongruent trial, relative to a congruent trial. However, it is unclear if this effect stems from a general control mechanism or a distinct process tied to cross-trial reengagement of the task set. We examine the relationship of the CSE with another measure of control referred to as the item-specific proportion congruency effect (ISPC), the finding that frequently occurring congruent items exhibit greater interference than items that are often incongruent. If the two effects reflect the same control mechanism, one should find interactive effects of CSE and ISPC. We report results from three experiments utilizing a vocal Stroop task that manipulated these two effects while controlling for variables that are often confounded in the literature. Across three experiments, we observed large CSE and ISPC effects. Importantly, these effects were robustly additive with one another (Bayes Factor for the null approaching 9). This finding indicates that the CSE and ISPC arise from independent mechanisms and suggests the CSE in Stroop may reflect a more general response adjustment process that is not directly tied to trial-by-trial changes in attentional control.

Effects of aerobic fitness on cognitive performance as a function of dual-task demands in older adults

The objective of this study was to examine the effects of aerobic fitness on cognitive performance under varying dual-task demands in older adults. Thirty-four participants (mean ± SD age: 68.6 ± 10.1 years, 24 females) were included in this study. VO₂ max was assessed with the Rockport 1-mile walk test (range = 6.68-45.57). Participants engaged in a cognitive task, the Modified Stroop Color Word Test (MSCWT) on a self-paced treadmill while simultaneously standing or walking. Performance on the Stroop Test was measured as interference of the accuracy score. Participants demonstrated over a 4-fold increase in SI when going from Incongruent to Switching MSCWT blocks across both standing and walking tasks. Furthermore, there was a significant interaction between the MSCWT block and VO₂ max in Stroop interference, such that Switching Stroop interference demonstrated greater changes due to VO₂ max, in comparison to Incongruent SI, even after controlling for age, gender, body mass index, and years of education as covariates in analyses. These results provide evidence of a relationship between aerobic fitness and cognition, suggesting that dual-task interference may provide a sensitive indicator of effects of an aerobic intervention program on the cognitive performance among older adults.

The flexibility of cognitive control: Age equivalence with experience guiding the way

Prior research has shown that aging is accompanied by changes in cognitive control. Older adults are less effective in maintaining an attentional bias in favor of goal-relevant information and are less flexible in shifting control relative to younger adults. Using a novel variant of the Stroop color-naming task, we tested the hypothesis that age-related differences in the flexible shifting of control may be small or absent when control is guided by experience (i.e., environmental input guiding attention). Younger and older adults named the color of color words in abbreviated lists of trials. In Experiment 1, experience within the early segment of the list was manipulated to encourage adoption of more (mostly congruent condition) or less (mostly incongruent condition) attention toward the word. More important, the middle and late portions were 50% congruent in both conditions. Older adults, like younger adults, demonstrated flexible acquisition and shifting of control settings (i.e., relative attention to word vs. color information). In Experiment 2 we replicated this finding. Additionally, we found that both age groups flexibly acquired and shifted control settings for "transfer" items (i.e., items that were 50% congruent in all lists and list segments), pointing to a generalizable (i.e., global) form of control rather than an item-specific mechanism. Discussion focuses on the role of experience-guided control in enabling flexible performance in older adults. (PsycINFO Database Record

Can the post-error effect mask age-related differences in congruency conditions when education and overall accuracy are controlled for?

OBJECTIVE

Age-related differences in stimulus-response congruency tasks have been attributed to older adults' greater difficulties in handling the irrelevant spatial-dimensional overlap between stimulus and response. However, performance on congruency tasks may also be influenced by the previous trial accuracy (i.e. post-error effect), which may affect young and older adults differently. The main objective of this study was to analyse age-related differences in the post-error effect as a function of congruency. In addition, we examined the meditational role of the Gratton effect on the age-related differences in the post-error slowing (PES) and post-error increased accuracy (PIA) as a function of congruency.

METHOD

The sample comprised 165 healthy adult participants with diverse educational attainment, divided into five age groups. Participants performed a spatial stimulus-response congruency task. Age-related differences in the post-error effect were analysed for each congruency condition taking into account educational attainment and overall accuracy. Statistical procedures were used to neutralize age-related processing speed effects on the PES.

RESULTS

PES was observed across all age groups, except the Very old group (aged 85-98 years), and it was not related to congruency condition. PIA was observed across age groups in all congruency conditions and was slightly higher in incongruent trials. Evidence of simultaneous PES and PIA was found for young participants and older participants under 85 years. The Very old group did not need to significantly slow down their responses after errors to improve accuracy. No age- related difference was found in the influence of the Gratton effect on PES or PIA as a function of congruency.

CONCLUSIONS

PES and PIA were observed in young adults and older adults under 85 years old. Evidence of simultaneous PES and PIA in the young and older age group (except for the Very old) indicates that the post-error effect can be interpreted in terms of recruitment of additional resources to prevent subsequent errors. Slightly higher accuracy was observed in the incongruent condition in post-error trials relative to pre-error correct trials across age groups.

Dynamic adjustments of attentional control in healthy aging

In standard attentional control tasks, interference effects are reduced following incongruent trials compared to congruent trials, a phenomenon known as the congruency sequence effect (CSE). Typical explanations of this effect suggest the CSE is due to changes in levels of control across adjacent trials. This interpretation has been questioned by the finding that older adults, individuals with impaired attentional control systems, have been shown to produce larger CSEs in the Stroop task compared with younger adult controls. In 2 experiments, we investigate the generality of this finding by examining how the CSE changes in healthy aging in 3 standard attentional control tasks-Stroop, Simon, and flanker-while controlling for additional confounds that have plagued some of the past literature. In both experiments, older adult participants exhibited a larger CSE in the Stroop task, replicating recent research, but smaller CSEs in both the Simon and flanker paradigms. These results are interpreted as reflecting a pathway priming mechanism in the Stroop task but a control adjustment process in Simon and flanker. Hence, there appears to be different mechanisms underlying the CSE which are engaged based on the type of attentional selection that is required by the task. More generally, these results question the use of the CSE in the Stroop task as a measure of dynamic adjustments in attentional control and highlight the importance of consideration of task-specific control systems underlying the CSE. (PsycINFO Database Record

The Generality of Dynamic Adjustments in Decision Processes across Trials and Tasks

There is a growing interest in understanding how aspects of binary decision-making change dynamically at the trial level. For example, in lexical decision, there is a well-established interaction between current and previous trial characteristics (e.g., lexicality and stimulus degradation) that suggests that participants adjust their decision processes based on the relative match in signal strength between the current and previous trial. The present study assessed the generality of this finding by examining the presence of such cross-trial adjustments in two new tasks, syntactic classification, and memory scanning. Stimulus degradation is manipulated in both tasks. Results indicate that response latencies are facilitated when salient aspects of the stimulus repeat across trials. These findings are interpreted within the context of a flexible processor that utilizes information from the prior target to prime the relevant processing pathway on the current trial. Candidate models that potentially can accommodate the pattern are briefly discussed.

Disentangling cognition and emotion in older adults: the role of cognitive control and mental health in emotional conflict adaptation

OBJECTIVE

Recent research suggests cognition has a bidirectional relationship with emotional processing in older adults, yet the relationship is still poorly understood. We aimed to examine a potential relationship between late-life cognitive function, mental health symptoms, and emotional conflict adaptation. We hypothesized that worse cognitive control abilities would be associated with poorer emotional conflict adaptation. We further hypothesized that a higher severity of mental health symptoms would be associated with poorer emotional conflict adaptation.

METHODS

Participants included 83 cognitively normal community-dwelling older adults who completed a targeted mental health and cognitive battery, and emotion and gender conflict-adaptation tasks.

RESULTS

Consistent with our hypothesis, poorer performance on components of cognitive control, specifically attention and working memory, was associated with poorer emotional conflict adaptation. This association with attention and working memory was not observed in the non-affective-based gender conflict adaptation task. Mental health symptoms did not predict emotional conflict adaptation, nor did performance on other cognitive measures.

CONCLUSION

Our findings suggest that emotion conflict adaptation is disrupted in older individuals who have poorer attention and working memory. Components of cognitive control may therefore be an important potential source of inter-individual differences in late-life emotion regulation and cognitive affective deficits. Copyright © 2016 John Wiley & Sons, Ltd.

Self-control predicts attentional bias assessed by online shopping-related Stroop in high online shopping addiction tendency college students

OBJECTIVE

The aim of this study was to examine the relationships of personality types (i.e., self-control, BAS/BIS) and online shopping addiction (OSA) behavior and to investigate whether high-OSA tendency individuals display attentional biases toward online shopping-related (OS-related) stimuli as well as the links between attentional bias and personality types.

METHOD

The study included 98 college students divided into three groups (i.e., high-, medium- and low-OSA) according to their OSA behavior. The personality types (i.e., self-control, BAS/BIS) and OSA behavior were investigated by questionnaires. The attentional bias was evaluated by the OS-related Stroop and dot-probe task (DPT) paradigms.

RESULTS

OSA was positively predicted by time spent on online shopping per day and average consumption for online shopping monthly, and negatively by self-control. High-OSA individuals displayed significant attentional biases toward OS-related stimuli in the Stroop, but not DPT paradigm. Moreover, the attentional bias toward OSA-related stimuli in high-OSA individuals was negatively correlated with self-control.

CONCLUSION

These findings demonstrated the critical role of self-control in OSA behavior and attentional bias to OS-related stimuli in high-OSA individuals, indicating that more importance should be attached to self-control for the clinical intervention of online shopping addiction in future studies.

Dynamic adjustment of lexical processing in the lexical decision task: Cross-trial sequence effects

There has been growing interest in dynamic changes in the lexical processing system across trials, which have typically been assessed via linear mixed effect modelling. In the current study, we explore the influence of previous trial lexicality and previous trial perceptual degradation on the effect of lexicality and degradation on the current trial. The results of analyses of three datasets (two previously published studies and a new study) provide evidence for a robust four-way interaction among previous trial lexicality and degradation and current trial lexicality and degradation effects. Discussion emphasizes how priming of relevant dimensions (clear vs. degraded or word vs. nonword) within the experimental context modulates the influence of degradation on the current trial as a function of lexicality. These results suggest that in lexical decision there are robust lingering effects of the previous stimulus and response that carry over to the current stimulus and response, and participants cannot tune task-related systems to only the present trial. Importantly, although these complex relationships are theoretically important regarding lexical and decision level processes, these complexities also reinforce Keith Rayner's emphasis on on-line eye-tracking measures during reading as the most straightforward window into word-level processes engaged during reading.

The protective role of long-term meditation on the decline of the executive component of attention in aging: a preliminary cross-sectional study

Life expectancy is constantly increasing. However, a longer life not always corresponds to a healthier life. Indeed, even normal aging is associated with a decline in different cognitive functions. It has been proposed that a central mechanism that could contribute to this widespread cognitive decline is an ineffective inhibitory attentional control. Meditation, to the other hand, has been associated, in young adults, to enhancement of several attentional processes. Nevertheless, attention is not a unitary construct. An influent model proposed the distinction of three subsystems: the alerting (the ability to reach and maintain a vigilance state), the orienting (the capacity of focusing attention on a subset of stimuli), and the conflict resolution or executive component (the ability to resolve conflict or allocate limited resources between competing stimuli). Here, we investigated, employing the Attentional Network Task (ANT), the specific impact of age on these three subcomponents, and the protective role of long-term meditation testing a group of older adults naïve to meditation, a group of age-matched adults with long-term practice of meditation, and a group of young adults with no previous meditation experience. We reported a specific decline of the efficiency of the executive component in elderly that was not observed in age-matched meditators. Our results are encouraging for the investigation of the potential beneficial impact of meditation on other cognitive processes that decline in aging such as memory. Moreover, they could inform geriatric healthcare prevention and intervention strategies, proposing a new approach for cognitive remediation in elderly populations.