During social interactions, there is a tendency for people to mimic the gestures and mannerisms of others, which increases liking and rapport. Psychologists have extensively studied the antecedents and consequences of mimicry at the social level, but the neural basis of this behavior remains unclear. Many researchers have speculated that mimicry is related to activity in the human mirror system (HMS), a network of parietofrontal regions that are involved in both action execution and observation. However, activity of the HMS during reciprocal social interactions involving mimicry has not been demonstrated. Here, we took an electroencephalographic (EEG) index of mirror activity-mu-suppression during action observation-in a pretest/post-test design with 1 of 3 intervening treatments: 1) social interaction in which the participant was mimicked, 2) social interaction without mimicry, or 3) an innocuous computer task, not involving another human agent. The change in mu-suppression from pre- to post-test varied as a function of the intervening treatment, with participants who had been mimicked showing an increase in mu-suppression during the post-treatment action observation session. We propose that this specific modulation of HMS activity as a function of mimicry constitutes the first direct evidence for mirror system involvement in real social mimicry.
Depending on individual differences in biological rhythms and diurnal preferences, people have long been described as either "larks" or "owls." Larks and owls differ greatly in personality aspects, but from the behavioral perspective it is unclear whether they have significant differences in terms of risky behaviors. Whether morning types or evening types are consistently more risk-taking or risk-averse in different domains remains unknown. This study adopted a general American adult sample to systematically investigate the relationship between chronotype and individuals' risky behaviors in different domains. By using different methods to measure risky behaviors in different domains, the current research obtained convergent results that morningness was negatively related only to financially risky behaviors for American adults. More specifically, by using the composite scale of morningness and the domain-specific risk attitude scale, Study 1 showed that for American adults, morning types were less likely than evening types to engage in financially risky behaviors (N = 212). In Study 2, after scenario-based methods were used to measure risky behavior, results showed that that participants engaged less in risky behaviors in the domains of gambling and investment (N = 187). A mediator test showed that the negative relationship between morningness and financially risky behaviors was partly mediated by individuals' self-control ability (self-control scale, Study 1).