Using facial EMG to investigate the effects of group membership and exclusion on the mimicry of smiles

It has been shown that excluded individuals are motivated to re-affiliate with others through autonomic behaviours, such as mimicry. Studies have also shown that people are more likely to mimic the behaviour of in-group members due to an in-group bias. The current study explores whether a combination of both group membership and exclusion plays a role in the mimicry of smiling. It was predicted that excluded individuals will be more accurate at discriminating between smiles and that excluded individuals would show more activity in response to the photos, particularly to genuine smiles. It was also predicted that individuals will show higher activity in the orbicularis oculi in response to genuine smiles and excluded participants are more likely to mimic photos of in-group targets with a genuine smile. Results revealed that participants showed more facial mimicry towards genuine smiles, thus suggesting a sensitivity to the differences in the smile types. However, the hypotheses were not supported. Instead, results showed that participants frowned at out-group targets and posed smiles while excluded participants frowned at genuinely smiling out-group targets. Additionally, the findings also revealed level of identification to be a contributing factor, where hidden effects were revealed after low identifiers were excluded from analyses. The findings seem to suggest that with the current manipulations, excluded participants showed out-group derogation in the form of frowning, rather than in-group bias via facial mimicry, in attempt to be re-established back into the in-group