The perception of spontaneous and volitional laughter across 21 societies

Data available at https://dataverse.harvard.edu/ dataverse/laughterperception</p

Investor’s pessimistic and false belief about trustworthiness and stake size in trust decision

Kuroda, K., Kamijo, Y., &amp; Kameda, T. (2021). Investor's pessimistic and false belief about trustworthiness and stake size in trust decision. Japanese Psychological Research, 63(2), 85–94. https://doi.org/10.1111/jpr.1228

Inequality biases third-party evaluation of decision-making for others

Kuroda, K., &amp; Saito, Y. (2021). Inequality biased third-party evaluation of decision-making for others. Letters on Evolutionary Behavioral Sciences, 12(2), 34-38. https://doi.org/10.5178/lebs.2021.87 The data and code that support the findings of this study have been deposited here

Majority rule can help solve difficult tasks even when confident members opt out to serve individual interests

Abstract When sharing a common goal, confident and competent members are often motivated to contribute to the group, boosting its decision performance. However, it is unclear whether this process remains effective when members can opt in or out of group decisions and prioritize individual interests. Our laboratory experiment (n = 63) and cognitive modeling showed that at the individual level, confidence, competence, and a preference for risk motivated participants’ opt-out decisions. We then analyzed the group-level accuracy of majority decisions by creating many virtual groups of 25 members resampled from the 63 participants in the experiment. Whereas the majority decisions by voters who preferred to participate in group decision making were inferior to individual decisions by loners who opted out in an easy task, this was reversed in a difficult task. Bootstrap-simulation analyses decomposed these outcomes into the effects of a decrease in group size and a decrease in voters’ accuracy accruing from the opt-in/out mechanism, demonstrating how these effects interacted with task difficulty. Our results suggest that the majority rule still works to tackle challenging problems even when individual interests are emphasized over collective performance, playing a functional as well as a democratic role in consensus decision making under uncertainty

Majority rule can help solve difficult tasks even when confident members opt out to serve individual interests

When sharing a common goal, confident and competent members are often motivated to contribute to the group, boosting its decision performance. However, it is unclear whether this process remains effective when members can opt in or out of group decisions and prioritize individual interests. Our laboratory experiment (n = 63) and cognitive modeling showed that at the individual level, confidence, competence, and a preference for risk motivated participants’ opt-out decisions. We then analyzed the group-level accuracy of majority decisions by creating many virtual groups of 25 members resampled from the 63 participants in the experiment.AQ1 Whereas the majority decisions by voters who preferred to participate in group decision making were inferior to individual decisions by loners who opted out in an easy task, this was reversed in a difficult task. Bootstrap-simulation analyses decomposed these outcomes into the effects of a decrease in group size and a decrease in voters’ accuracy accruing from the opt-in/out mechanism, demonstrating how these effects interacted with task difficulty. Our results suggest that the majority rule still works to tackle challenging problems even when individual interests are emphasized over collective performance, playing a functional as well as a democratic role in consensus decision making under uncertainty

Behavioral and neuro-cognitive bases for emergence of norms as socially shared realities via dynamic interaction (Pre-registration for the online experiment)

Two follow up experiments (for details of the main experiments, Kuroda et al. (2020). https://doi.org/10.31234/osf.io/sk9eq

Bilateral (but not unilateral) interaction creates and cements norms at the covert psychophysical level: A behavioral and an fMRI study

Social norms, including values, beliefs and even perceptions about the world, are preserved and created through repeated interactions between individuals. However, whereas neuro-cognitive research on social norms has used the “unilateral influence” paradigm focusing on people’s reactions to extant standards, little is known about how our basic perceptions and judgments are shaped as new norms through bilateral interaction. Here, using a simple estimation task, we investigated the formation of perceptual norms using two experiments coupled with computational modeling. In the behavioral experiment, participants in dyads repeatedly estimated the number of dots on a screen and viewed each other’s answers. In the fMRI experiment, we manipulated the interaction process by pairing each participant with a computer agent which adjusted its estimations reciprocally to participants’ estimations (bilateral agent) or did not (unilateral). The results indicated that only the bilateral interaction yielded convergence of participants’ covert psychophysical functions (relations between subjective estimations and the actual number of dots) as well as overt behavioral responses within a pair. Bilateral interaction also increased the stability (reliability) of the covert function within each individual after interaction. Neural activity in the mentalizing network (right temporoparietal junction and dorsomedial prefrontal cortex) during interaction modulated the stabilization of the psychophysical function. These results imply that bilateral interaction helps people to cognitively anchor their views with each other. Such spontaneous perspective sharing can yield a shared covert “generative model” that enables endogenous agreement on totally new targets ― one of the key features of social norms

Kordsmeyer et al. (preprint) Halo effect of faces and bodies: Cross-cultural similarities and differences between German and Japanese observers

According to the halo effect, person perceptions are globally biased by specific traits or characteristics. Attractive people are attributed positive traits like prosociality, health, and dominance. Due to a strong focus on facial stimuli it remains unclear whether this effect can also be found for bodies. Furthermore, most studies involved observers from individualistic cultures. This preregistered study explored the consistency of halo effects for men’s faces and bodies for individualistic and collectivistic observers. Facial photos and 3D body scans of 165 German men were judged separately for attractiveness, prosociality, health, and physical dominance by 123 German and 100 Japanese observers. Results were mostly consistent between both observer groups and revealed strong attractiveness halo effects for faces and bodies, and a physical dominance halo effect for bodies. This study provides new insights on consistent halo effect biases in person perception for faces and bodies for observers with different cultural backgrounds