People are perceived to be more attractive when in a group because any facial asymmetries or other imperfections appear less noticeable, research suggests. This has been dubbed “the cheerleader effect.” Researchers believe that when multiple faces are in a group, the viewer’s visual system combines all of the collective features and averages them out, which typically results in a face that is more attractive because all of the individual imperfections are diluted. When the visual system sees the face of just one person, it is able to focus more closely on all of the individual asymmetries or disproportionate features and judge that person’s attractiveness more harshly.
More about perceived attractiveness:
One study found that, upon first impression, people are able to accurately determine the personality traits of people whom they find attractive.
Symmetrical features generally are viewed as more attractive because, from an evolutionary standpoint, asymmetry is associated with genetic mutations that could result in a lower survival rate.
Having similar inheritable personality traits accounts for about one-third of a person’s decision when choosing a mate, research suggets.