Effects of experimental situation on group cooperation and individual performance: Comparing laboratory and online experiments.

With the spread of online behavioral experiments, estimating the effects of experimental situations and sample heterogeneity is increasing in discussions of the generalizability of data. In this study, we examined how the experimental situations (laboratory/online) affected group cooperation and individual performances. The participants were Japanese university students, randomly assigned to laboratory or online experiments. For the group cooperation task, they were asked to perform the public goods game with or without punishment, but no effect of the experimental situation was found both for cooperative and punitive behaviors. For the individual tasks, participants were asked to perform tasks including a creative task and a dull task. We manipulated the presence or absence of an external incentive. As a result, there was no significant difference between the experimental situations with one exception: only in the laboratory situation was the performance of the difficult creative task lower in the presence of an external incentive. Furthermore, we conducted as an additional experiment using the same treatments for a Japanese online-worker sample. This sample was less cooperative in the public goods game than the student sample, both with and without punishment. In addition, the presence of external incentives facilitated performance of the online-worker sample only for the dull task. We discuss the similarities and differences with previous studies that examined the effects of experimental situations and sample heterogeneity, and the implications for remote work in the real world.

Anxiety, reactivity, and social stress-induced cortisol elevation in humans.

OBJECTIVES: Traditionally, it has been hypothesized that highly anxious/emotionally reactive subjects may have exaggerated social stress response. We examined the relationship between self-reported anxiety, emotional reactivity, and social stress response. METHODS: We investigated the relationship between personality scales of trait-state anxiety, subjective autonomic reactivity, and salivary cortisol levels before and after social stress exposure (Trier Social Stress Test) in 20 men. RESULTS: Significant positive correlations between anxiety, subjective autonomic reactivity, and basal cortisol levels were observed, while neither anxiety nor subjective autonomic reactivity was correlated with social stress-induced cortisol elevation. CONCLUSIONS: The present results indicate (i) subjects with higher degrees of trait anxiety/subjective autonomic reactivity have higher basal cortisol levels, and (ii) in contrast to the traditional view, anxious personality is not strongly associated with exaggerated cortisol response to social stress.

Interpersonal trust and social stress-induced cortisol elevation.

A neuroendocrine correlate of interpersonal trust is relatively unknown. We investigated the relationship between an interpersonal trust-related personality (General Trust Scale) and cortisol elevation induced by social stress in 20 men. Spearman's rank order correlation analysis revealed a significant negative correlation between social stress-induced cortisol elevation and General Trust Scale. The present results indicate subjects with higher degrees of interpersonal trust have lower levels of neuroendocrine response to social stress.

Social stress-induced cortisol elevation acutely impairs social memory in humans.

Although stress is known to affect the memory process, little has been elucidated regarding its effect on social memory. In this study, 30 subjects' social memory (face-name association memory) performance was tested. Twenty subjects were exposed to social stress with a subsequent test of social memory, while the remaining ten subjects served as controls. Free cortisol was determined via saliva samples taken before and after the social stress exposure. Because stress hormones might have biphasic actions on neurons, we separated the subjects with cortisol elevations between high and low responders. The high responders had significantly impaired social memory. Furthermore, we observed a negative relation between social stress-induced cortisol elevation and social memory. These results indicate that social stress acutely impairs social memory.