The cheerleader effect, also known as the group attractiveness effect, is the cognitive bias which causes people to think individuals are more attractive when they are in a group. The term was backed up by research by Drew Walker & Edward Vul (2013) and drs. Stefan van Esch et al. (2015).
The phrase was coined by the character Barney Stinson in "Not a Father's Day", an episode of the television series How I Met Your Mother, first aired in 2008. Barney points out to his friends a group of women that initially seem attractive, but who all seem to be very ugly when examined individually. This point is made again by Ted and Robin later in the episode, who note that some of Barney's friends also only seem attractive in a group.
Across five studies by Walker and Vul (2013), participants rated the attractiveness of male and female faces when shown in a group photo, and an individual photo, with the order of the photographs randomised. The people photographed got higher scores for their group photos.
This effect occurs with male-only, female-only and mixed gender groups, and both small and large groups. The effect occurs to the same extent with groups of four and 16 people. Participants in studies looked more at the attractive people than the unattractive people in the group. The effect does not occur because group photos give the impression that individuals have more social or emotional intelligence: this was shown to be the case by a study which used individual photos grouped together in a single image, rather than photos taken of people in a group.
When all three of these phenomena are taken together, the individual faces will seem more attractive in a group, as they appear more similar to the average group face, which is more attractive than members' individual faces.
A 2015 study by van Osch et al. confirmed the results obtained by Walker and Vul.
The research team offered two different explanations for the group attractiveness effect:
They claim that selective attention fits better the gathered data.
A 2015 replication of Walker and Vul's study failed to show any significant results for the group attractiveness effect. The research team hypothesized that this may be due to cultural differences, since the replication study was performed in Japan.