The crude ostracism detection system: Pupils react to minimal cues of exclusion

When people are rejected by others, they typically feel an immediate sense of pain—referred to as social pain. Social pain is hypothesized to be the alarm response of a “quick and crude” ostracism detection system, a system that is highly sensitive to even minimal signs of exclusion. Physiological reactivity has been found to accompany this social pain, but it is unclear whether the physiological mechanism underlying the ostracism detection system is also “quick and crude.” To test whether physiological reactivity to exclusion is “quick and crude,” the present study investigated whether pupil dilation (an index of physiological reactivity) differs when detecting exclusion from human entities versus nonhuman entities and when experiencing versus witnessing exclusion using a Cyberball paradigm. Experiment 1 showed that pupil size decreased less when viewing players who were exclusive than those who were inclusive, regardless of whether the players were human (i.e., undergraduate students) or nonhuman (i.e., computerized) entities. The same pupil reactivity pattern was observed in Experiment 2 after participants watched interactions in which another person was included or excluded by human or nonhuman entities. In Experiment 3, participating in real-life interactions with human players did not cause pupil reactivity to be greater to human players compared to nonhuman players, but pupil size again decreased less when viewing exclusive players compared to inclusive players. Across all three experiments, pupil size decreased less when viewing players who were exclusive than inclusive regardless of the social identity of the players. These findings support the idea of a highly sensitive, “quick and crude” physiological mechanism that underlies the ostracism detection system.