Meta-Analysis of Social Presence Effects on Stroop Task Performance.

In this paper, we conducted a meta-analytic review to examine the impact of social presence on individuals' performance on the Stroop task, shedding light on the cognitive processes underlying social facilitation. We followed PRISMA guidelines to identify and include 33 relevant studies in a multivariate random-effects meta-analysis. Our results show that social presence reliably modulates Stroop interference (a measure of cognitive control); specifically, participants exhibit lower Stroop interference when performing the task in the presence of others compared to performing it in isolation. We also found that the strength of the effect varies depending on the type of social presence: it is stronger with an attentive audience compared to an inattentive one, and null with an evaluative audience. Additionally, different features of the Stroop task itself moderate the effect; the effect is stronger for the classic version of the task compared to the semantic version, and for experiments that use mixed within-block trials compared to those with homogenous blocks. We also observed a negative relationship between the number of trials and the magnitude of the effect. Overall, these findings provide insights into the mechanisms by which the presence of others affects performance on the Stroop task, and how they align with social facilitation theories.

A meta-analytical review of the familiarity temporal effect: Testing assumptions of the attentional and the fluency-attributional accounts.

The current meta-analysis accumulates empirical findings for the familiarity temporal effect (FTE) in duration judgments (the duration of more familiar stimuli is judged to be longer than that of less familiar stimuli). It brings together data from 2 separate literatures: time perception and processing fluency. In doing so, this review offers more and stronger evidence for testing the reliability of the effect; it defines the relevant moderators for addressing the validity of the 2 main explanations for the FTE: the attentional and the fluency-attributional hypotheses. The analysis (random effect model) of a total of 128 experiments (N = 3,338) showed that the effect of familiarity on perceived short durations (seconds) is highly reliable (g = .52); the same (or a similar) effect also occurs for other fluency manipulations (g = .51). The analysis supports assumptions generated by both the attentional and the fluency-misattributional explanations, suggesting that more research is needed to understand their possible dynamic relationship. Hence, this meta-analysis provides important guidance for future research with regard to time estimates. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

The perception of time is dynamically interlocked with the facial muscle activity.

Time perception relies on the motor system. Involves core brain regions of this system, including those associated with feelings generated from sensorimotor states. Perceptual timing is also distorted when movement occurs during timing tasks, possibly by interfering with sensorimotor afferent feedback. However, it is unknown if the perception of time is an active process associated with specific patterns of muscle activity. We explored this idea based on the phenomenon of electromyographic gradients, which consists of the dynamic increase of muscle activity during cognitive tasks that require sustained attention, a critical function in perceptual timing. We aimed to determine whether facial muscle dynamic activity indexes the subjective representation of time. We asked participants to judge stimuli durations (varying in familiarity) while we monitored the time course of the activity of the zygomaticus-major and corrugator-supercilii muscles, both associated with cognitive and affective feelings. The dynamic electromyographic activity in corrugator-supercilii over time reflected objective time and this relationship predicted subjective judgments of duration. Furthermore, the zygomaticus-major muscle signaled the bias that familiarity introduces in duration judgments. This suggests that subjective duration could be an embodiment process based in motor information changing over time and their associated feelings.

Testosterone response to competition in males is unrelated to opponent familiarity or threat appraisal.

It has been proposed in the literature that the testosterone (T) response to competition in humans may be modulated by cognitive variables. In a previous experiment with a female sample we have reported that opponent familiarity and threat appraisal moderated the T response to competition in women. With this experiment we aim to investigate if these variables have the same impact on males T response to competition, extending the previous findings in our lab. Forty male participants (20 dyads) were recruited to engage in a same sex, face to face competition using the Number Tracking Test as a competitive task. Levels of T, cortisol (C) and dehydroepiandrosterone (DHEA) were measured before and 20 min after the competition. Results show that losers report higher levels of threat than winners and increased their T levels after the competition, however this T change was not predicted by opponent familiarity or threat appraisal. No variation was detected for C and DHEA levels. These findings suggest that there could be sex differences for the moderators/mediators of the T response to competition in humans.