Acute stress affects prospective memory functions via associative memory processes

The effect of ostracism on prospective memory in problem solving

Successfully generating plans, while seemingly straightforward, can be riddled with external and internal interferences. One important possible source of interference is ostracism, which has been consistently shown to induce negative psychological effects in various executive functions. Therefore, understanding the impact of unforeseen ostracism on planning is vital to a broad spectrum of the population, from university students, whose self-esteem partly derives from social acceptance, to healthcare professionals, whose performance oftentimes relies on peer feedback. An individual's ability to navigate through intended actions is an evaluation of their prospective memory (PM), which is traditionally divided into three consecutive phases: (1) planning, (2) recall, and (3) performance. This study primarily focused on the impacts of ostracism via Cyberball simulation on the first two phases of PM in the Tower of London (TOL), an assessment of executive functioning designed specifically to test planning ability during problem solving. Using Bayesian analysis, the study found substantial evidence of there being no difference in planning success between social exclusion and inclusion conditions. However, an individual's sex had significant effects on their planning success at baseline (i.e., inclusion condition). Surprisingly, there was no difference in performance between male participants and female participants when excluded, suggesting that ostracism may play an equalizing role. In addition, male participants both listed more moves at planning and recalled more moves, which led to no difference between sexes in terms of recall percentage. This study underscores a need to consider various factors such as sex and differing perceptions of ostracism when analyzing and addressing problem solving performance.

Acute psychosocial stress impairs intention initiation in young but not older adults

Acute psychosocial stress has been shown to impair memory and cognitive control in young adults. So far, only very little empirical research is available concerning possible adult age differences in acute stress effects on cognition in general and cognitive control in particular. Accordingly, the present study set out to test these effects in a controlled laboratory setting comparing performance in a prospective memory task requiring the deployment of proactive cognitive control to successfully implement intentions. Sixty-six young (19-34 years) and 57 older adults (60-82 years) were either exposed to an established psychosocial stress procedure (Trier Social Stress Test) or an active control condition. Stress responses were measured on a fine-grained level across the entire procedure using subjective and physiological stress markers. Results suggest that the stress induction was equally successful in both age groups. While stress impaired prospective memory ability in young adults, it did not affect performance in the older adults. In particular, young adults under acute stress were more likely to completely fail the initiation of the prospective memory task resulting in zero performance. The missing stress effect on prospective memory in older adults is in line with previous studies examining broader mood effects on PM and suggests the exciting possibility that increasing age may act as a resilience factor against deterioration of cognitive control in emotionally challenging situations. AUTHOR NOTES: We thank Florence Caccia, Marta Guidotti, Nikol Hiller, Nada Kojovic, Raphaëlle Martin-Casas and Clémence Voirin for assistance with data collection, Robert Miller for advice concerning the data analyses and Antje Petzold, Jana Strahler and Moritz Walser for their advice regarding study and manuscript preparation. Preparation of this manuscript was funded by a grant (KL2303/5-1) from the Deutsche Forschungsgemeinschaft (DFG) to MK and CK.

Does older adults' cognition particularly suffer from stress? A systematic review of acute stress effects on cognition in older age

This literature review provides the first comprehensive qualitative and quantitative systematic synthesis of acute laboratory stress effects on older adults' cognition by specifying the direction and magnitude of those effects both overall and for different cognitive processes separately. A systematic literature search was performed, and effect sizes estimated whenever possible. We found meta-analytical evidence that stress has negative effects on older adults' verbal fluency (g_adj = -0.53, 95 % CI [-2.70, 1.63]), null-to-negative effects on episodic memory (g_adj = -0.26, 95 % CI [-0.44, -0.08]), null effects on executive functions (g_adj = 0.07, 95 % CI [-0.31, 0.46]), and enhancing effects on working memory (g_adj = 0.16, 95 % CI [-0.01, 0.33]). Relating these findings to those in young adults, notable differences emerged for some cognitive functions, such as opposing effects on working memory between age groups. Our review further reveals that stress effects on older adults' memory retention, associative memory, prospective memory, interference control or cognitive flexibility are heavily understudied. We provide a conceptual and methodological framework for future studies in older adults.

A Standardized Prospective Memory Evaluation of the Effects of COVID-19 Confinement on Young Students

The restriction imposed worldwide for limiting the spread of coronavirus disease 2019 (COVID-19) globally impacted our lives, decreasing people’s wellbeing, causing increased anxiety, depression, and stress and affecting cognitive functions, such as memory. Recent studies reported decreased working memory (WM) and prospective memory (PM), which are pivotal for the ability to plan and perform future activities. Although the number of studies documenting the COVID-19 effects has recently blossomed, most of them employed self-reported questionnaires as the assessment method. The main aim of our study was to use standardized tests to evaluate WM and PM in a population of young students. A sample of 150 female psychology students was recruited online for the administration of two self-reported questionnaires that investigated psychological wellbeing (DASS-21), prospective, and retrospective memory (PRMQ). Subjects were also administered two standardized tests for WM (PASAT) and PM (MIST). We found increased anxiety, depression, and stress and decreased PM as measured by self-reports. The perceived memory failures agreed with the results from the standardized tests, which demonstrated a decrease in both WM and PM. Thus, COVID-19 restriction has strongly impacted on students’ mental health and memory abilities, leaving an urgent need for psychological and cognitive recovery plans.

Acute stress reduces the emotional attentional blink: Evidence from human electrophysiology

The present study is the first to examine the time-dependent mechanism of acute stress on emotional attentional blink (EAB) with event-related potential (ERP) measures. We explored the stage characteristics of stress affecting EAB, whether it affects the early selective attention process (marked by early posterior negativity) or the late working memory consolidation (marked by late positive potential). Sixty-one healthy participants were exposed to either a Trier Social Stress Test (TSST) or a control condition, and salivary cortisol was measured to reflect the stress effect. ERPs were recorded during an attentional blink (AB) paradigm in which target one (T1) were negative or neutral images. Results showed stress generally reduced AB effects. Specifically, stress promoted the early selective attention process of target two (T2) following a neutral T1 but did not affect T2 consolidation into working memory. Correlational analyses further confirmed the positive effect of cortisol and negative emotional state on AB performance. Moreover, the ERP results of acute stress on AB conformed to the trade-off effect between T1 and T2; that is, stress reduced T1 late working memory consolidation and improved T2 early selective attention process. These findings further demonstrated that stress did not change the central resource limitation of AB. In general, stress generates a dissociable effect on AB early- and late-stage processing; namely, acute stress reduce the AB effect mainly from the improvement of participants' overall ability to select the targets in the early stage.

Bedtime Stress Increases Sleep Latency and Impairs Next-Day Prospective Memory Performance

The cognitive construct of prospective memory (PM) refers to the capacity to encode, retain and execute delayed intentions (e.g. to remember to buy milk on the way home). Although previous research suggests that PM performance is enhanced by healthy sleep, conclusions tend to be drawn based on designs featuring ecologically unnatural manipulations (e.g. total sleep deprivation). This study investigates whether a more common everyday experience (bedtime stress) affects next-day PM performance and, in so doing, also contributes to the heretofore inconsistent literature on stress and PM. Forty young adults received PM task instructions and were then assigned to either a stress condition (exposure to a laboratory-based stress-induction manipulation; n = 20, 9 women) or a non-stress condition (exposure to a non-stressful control manipulation; n = 20, 12 women). After completing the experimental manipulation, all participants had their objective sleep quality measured over a full night of polysomnographic monitoring. Upon awakening, they completed the PM task. Analyses detected significant between-group differences in terms of stress outcomes, sleep quality and PM performance: Participants exposed to the manipulation experienced heightened signs of stress (captured using a composite variable that included self-report, psychophysiological and endocrinological measures), had longer sleep latencies and poorer sleep depth and displayed significantly longer reaction times to PM cues. An interaction between experimental condition (being exposed to the stressor) and disrupted sleep (longer sleep latency) significantly predicted poorer next-day PM reaction time. We interpret these findings as indicating that bedtime stress, which leads to heightened presleep arousal, affects sleep processes and, consequently, the deployment of attentional resources during next-day execution of a delayed intention.

Prospective memory under acute stress: The role of (output) monitoring and ongoing-task demands

Prospective memory (PM) refers to the ability to postpone retrieval and execution of intended actions until the appropriate situation (PM cue) has come, while engaging in other ongoing activities or tasks. In everyday live we often perform PM tasks in stressful situations. While it has been shown that acute stress does not impair PM-cue identification and intention retrieval, little is known about acute stress effects on PM performance and memory for having performed an action (output monitoring) under varying ongoing-task demands. Here we investigated this in eighty healthy participants who performed event-based PM tasks during low- and high-demanding ongoing working memory tasks after having undergone either a standardized stress induction (Maastricht Acute Stress Test) or a standardized control protocol. Successful stress induction in the stress group compared to the no-stress group was confirmed by increased salivary cortisol, an indicator of stress-related hypothalamus-pituitaryadrenal axis activity, throughout the event-based PM tasks. Nevertheless, not-only PM-cue identification but also output monitoring remained fully intact after stress induction. The absence of these effects was independent of ongoing-task demands. Nonetheless, we replicated recent findings of a stress-induced reduction in performance cost of monitoring for PM-cue occurrences. Taken together our findings suggest that acute stress alters PM monitoring by enhancing selective attention, decreasing PM response thresholds or by shifting performance towards more automatic processes in PM, while not affecting PM-cue identification and output monitoring.

Joint effects of stress and chronic cannabis use on prospective memory

RATIONALE

Prospective memory pervades our daily lives and failures can have detrimental consequences. This ability to execute delayed intentions may be impacted by stress, yet few studies have examined these effects. Moreover, as many cannabis users report using cannabis to cope with stress, it is important to understand how stress impacts memory in cannabis users.

OBJECTIVES

We assessed the effects of acute and chronic stress on prospective memory to examine whether stress differentially impacts prospective memory in cannabis users vs. non-users.

METHODS

Forty cannabis users and 42 non-users were assigned an episodic and a habitual prospective memory test before completing either the stress or no stress condition of the Maastricht Acute Stress Test (MAST). Participants were instructed to execute the habitual test during the MAST and the episodic test shortly after the MAST. Chronic stress was measured using the Perceived Stress Scale, and acute stress was measured using subjective ratings and cortisol.

RESULTS

There was a main effect of acute stress indicating that stress detrimentally impacted habitual prospective memory performance. Although there was not a significant stress x cannabis interaction, further planned comparisons indicated the habitual prospective memory impairment was selective to cannabis users. There were also significant negative correlations between (i) episodic prospective memory and both subjective stress as well as chronic stress, and (ii) habitual prospective memory and change in subjective stress.

CONCLUSIONS

This study is the first to reveal detrimental effects of acute stress on prospective memory performance, which may be exacerbated in cannabis users.

Stress and prospective memory: What is the role of cortisol?

Studies investigating effects of acute stress on Prospective Memory (PM) so far yielded heterogeneous findings. Although results were commonly attributed to stress-induced changes in cortisol, past research did not disentangle effects of cortisol from the effects of sympathetic nervous system (SNS) activation and cognitive reappraisal. The present study therefore aimed at investigating the mere effect of cortisol on PM tasks that differently involve prefrontal brain regions (nonfocal vs. focal PM tasks) via a placebo-controlled oral pharmacological intake of 10 mg hydrocortisone mimicking physiological responses to stress. Contrary to our prediction, enhanced levels of cortisol did not affect PM accuracy and monitoring costs, neither for the focal nor the nonfocal PM tasks. These results suggest that changes of cortisol levels do not underlie potential stress effects on PM. Further exploratory results revealed that PM performance was higher in the 3 pm than in the 1 pm placebo group. This means that PM performance, independently of effects of cortisol, seem to vary throughout the day.