Conceptual precision is key in acute stress research: A commentary on Shields, Sazma, & Yonelinas, 2016

Flexible processing of distractor stimuli under stress

Acute stress is assumed to affect executive processing of stimulus information, although extant studies have yielded heterogeneous findings. The temporal flanker task, in which a target stimulus is preceded by a distractor of varying utility, offers a means of investigating various components involved in the adjustment of information processing and conflict control. Both behavioral and EEG data obtained with this task suggest stronger distractor-related response activation in conditions associated with higher predictivity of the distractor for the upcoming target. In two experiments we investigated distractor-related processing and conflict control after inducing acute stress (Trier Social Stress Test). Although the stressed groups did not differ significantly from unstressed control groups concerning behavioral markers of attentional adjustment (i.e., Proportion Congruent Effect), or event-related sensory components in the EEG (i.e., posterior P1 and N1), the lateralized readiness potential demonstrated reduced activation evoked by (predictive) distractor information under stress. Our results suggest flexible adjustment of attention under stress but hint at decreased usage of nominally irrelevant stimulus information for biasing response selection.

Acute stress influences the emotional foundations of executive control: Distinct effects on control-related affective and cognitive processes

Acute stress is known to influence performance on various task outcomes indicative of executive functioning (i.e., the top-down, goal-directed control of cognition and behavior). The most common interpretation of these effects is that stress influences control processes themselves. Another possibility, though, is that stress does not impair control per se, but instead alters the affective dynamics underlying the recruitment of control (e.g., reducing the extent to which making an error is aversive), resulting in less recruitment of control and thus poor performance. To date, however, no work has examined whether stress effects on executive function outcomes are driven by affective dynamics related to the recruitment of control. In the current study, we found that acute stress influenced-and cortisol responses related to-both executive control-related performance outcomes (e.g., post-error slowing) and control-related affective dynamics (e.g., negative affect following recruitment of control) in a modified Stroop task, but that these effects appeared to be independent of each other: The effects of stress on, and associations of cortisol with, control-related cognitive outcomes were not statistically mediated by task- or control-related affective dynamics. These results thus suggest that although stress influences affective dynamics underlying executive function, the effects of stress on executive function outcomes appear to be at least partially dependent on nonaffective processes, such as control processes themselves.

Induction of acute stress through an internet-delivered Trier Social Stress Test as assessed by photoplethysmography on a smartphone

Recent studies have demonstrated the feasibility of administering the Trier Social Stress Test (TSST) through the internet, with major implications for promoting inclusivity in research participation. However, online TSST studies to date are limited by a lack of control groups and the need for biological measures of stress reactivity that can be fully implemented online. Here, we test smartphone-based photoplethysmography as a measure of heart rate reactivity to an online variant of the TSST. Results demonstrate significant acceleration in heart rate and heightened self-reported stress and anxiety in the TSST condition relative to a placebo version of the TSST. The placebo condition led to a significant increase in self-reported stress and anxiety relative to baseline levels, but this increase was smaller in magnitude than that observed in the TSST condition. These findings highlight the potential for smartphone-based photoplethysmography in internet-delivered studies of cardiac reactivity and demonstrate that it is critical to utilize random assignment to a control or stressor condition when administering acute stress online.

Are Energy-Vulnerable Households More Prone to Informative, Market, and Behavioral Biases?

The present paper focuses primarily on investigating whether energy-vulnerable households are more prone to informative, market, and behavioral biases. In this direction, a stated preference approach was used to elicit information about human behavior and cognitive barriers in the context of energy poverty based on both subjective and objective indicators. For the purposes of the survey, a questionnaire was developed that included around 40 questions about housing conditions and information, market, and behavioral barriers related to energy efficiency, energy vulnerability, etc., and specific survey hypotheses were tested employing non-parametric tests. The survey was carried out between November 2020 and January 2021 involving residents of Metsovo, a mountain settlement in Greece. In total, 303 participants took place in the survey through personal interviews, which were conducted remotely due to the COVID-19 pandemic-related distancing measures, using a video platform. The analysis shows that households that face thermal discomfort or are in arrears on energy bills seem to be more prone to certain behavioral and other biases. This conclusion is not confirmed for households that face condensation, mold and damp problems or are classified as energy-poor under the “ten percent rule”. The main conclusion drawn is that the income status of the household plays a greater role compared to its classification as energy vulnerable. Nevertheless, the findings of the study need to be confirmed by future research, because the research specifically on how energy poverty affects people’s decision making is extremely limited. In any case, the results are worrisome and illustrate the need for more effective energy poverty policies that will take into account the effects of scarcity on household decision making.

Stress and cognition: A user's guide to designing and interpreting studies

Fueling the rapid growth in our understanding of how stress influences cognition, the number of studies examining the effects of stress on various cognitive processes has grown substantially over the last two decades. Despite this growth, few published guidelines exist for designing these studies, and divergent paradigm designs can diminish typical effects of stress or even reverse them. The goal of this review, therefore, is to survey necessary considerations (e.g., validating a stress induction), important considerations (e.g., specifying the timing of the stressor and cognitive task), and best practices (e.g., using Bayesian analyses) when designing a study that aims at least in part to examine the effects of acute stress on some cognitive process or function. These guidelines will also serve to help readers of these studies interpret what may otherwise be very confusing, anomalous results. Designing and interpreting studies with these considerations and practices in mind will help to move the field of stress and cognition forward by clarifying how, exactly, stress influences performance on a given cognitive task in a population of interest.

Acute stressor effects on cognitive flexibility: mediating role of stressor appraisals and cortisol

Acute stressor experiences may influence cognition, possibly through actions of cognitive flexibility, which comprises the ability to modify cognitive and behavioral strategies in response to changing environmental demands. In the present investigation, we examined the effects of an acute psychosocial stressor (the Trier Social Stress Test) on a specific form of cognitive flexibility, namely that of set-shifting, which was assessed by the Berg's Card Sorting Task (BCST). Among undergraduate students, the stressor promoted better performance on the BSCT relative to that evident among nonstressed individuals, including a reduction of perseverative (an index of enhanced set-shifting) and non-perseverative errors. They also required fewer trials to learn the first sorting category, reflecting augmented acquisition of an attentional set, but did not differ in the ability to maintain a set. Moreover, increased cortisol levels specifically mediated the enhancing effects of the acute stressor on set-shifting, but not the ability to acquire and maintain an attentional set. However, this enhancing effect was minimized among individuals who appraised the stressor as being uncontrollable. These data indicate that an acute, social-evaluative stressor can facilitate certain forms of cognitive flexibility, such as set-shifting. The present investigation also highlights the value of focusing on psychological and physiological mediators in determining the impact of stressful experiences on cognitive functioning. Lay summary A brief social stressor (public speaking) can have an enhancing effect on mental flexibility, and this seems to be related to the stress hormone, cortisol. This cognitive enhancing effect, however, might be minimized if a stressful situation is perceived as beyond a person's control.