Abstract

People have a fundamental and a critical need to belong. Social exclusion impairs this need and rejected
individuals must seek to regain acceptance from others. It is known that such individuals show an increased
preference for smiles. On the other hand, social exclusion sometimes leads to aggression. It is possible that this
contradiction is modulated by acceptance and the level of control, such that prosocial behavior occurs in
response to evidence of social affirmation, whereas aggression increases in response to reductions in the level of
control. However, little is known about the impact of smiles without social affirmation, or the interaction
between the effects of smiles and the level of control. In this study, we investigated the effects of such smiles by
manipulating an excluder’s facial expressions (i.e., neutral and smiling faces) and similarity to the participant
(i.e., level of control). We hypothesized that smiling excluders that are similar to the participant would increase
aggression in the participant, presumably because being rejected by a similar partner reduces the level of control.
In support of our hypothesis, results indicated that when excluders smiled, increased aggression was directed at
those excluders that were similar to the participant. Our findings imply that a smile of an excluder directed at the
person being excluded is one of the risk factors for aggressive behaviors in the excluded person.

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