Few studies have examined the underlying mechanism that links social behavior to reward and punishment systems in different personality types. The current study was designed to investigate this mechanism by examining autonomic nervous arousal and behavioral responses to both rewarding and punishing stimuli in extrovert and introvert personalities.

The stop signal task, including dominant process and non-dominant process, and the monetary incentive delay task （MID）were performed by twenty extroverted and twenty introverted undergraduates. In the MID task, both potentially rewarding and potentially punishing stimuli were shown to the participants, and then they were required to make an adaptive response to obtain a positive outcome or to avoid a negative outcome.

The behavioural results showed that both extroverts and introverts responded more quickly to rewarding stimuli compared to punishing and neutral stimuli in dominant process, while only introverts made disinhibitory responses in non-dominant process in the stop signal task. Moreover, arousal data also showed that both groups of participants had faster heart rates and higher skin conductance levels to rewarding and punishing significant stimuli than to neutral stimuli; however, introverts had a higher skin conductance level to rewarding and punishing significant stimuli compared to extroverts.

The results suggested that extroverts exhibited BAS activation, while introverts exhibited BIS activation in the context of both rewarding and punishing stimuli. Therefore, the two groups produced different response modes during the dominant process and non-dominant process.