People seem to differ in their visual search performance involving emotionally expressive faces when these expressions are seen on faces of others close to their age (peers) compared to faces of non-peers, known as the own-age bias (OAB). This study sought to compare search advantages in angry and happy faces detected on faces of adults and children on a pool of children (N = 77, mean age = 5.57) and adults (N = 68, mean age = 21.48). The goals of this study were to (1) examine the developmental trajectory of expression recognition and (2) examine the development of an OAB. Participants were asked to find a target face displaying an emotional expression among eight neutral faces. Results showed that children and adults found happy faces significantly faster than angry and fearful faces regardless of it being present on the faces of peers or non-peers. Adults responded faster to the faces of peers regardless of the expression. Furthermore, while children detected angry faces significantly faster compared to fearful ones, we found no such difference in adults. In contrast, adults detected all expressions significantly faster when they appeared on the faces of other adults compared to the faces of children. In sum, we found evidence for development in detecting facial expressions and also an age-dependent increase in OAB. We suggest that the happy face could have an advantage in visual processing due to its importance in social situations and its overall higher frequency compared to other emotional expressions. Although we only found some evidence on the OAB, using peer or non-peer faces should be a theoretical consideration of future research because the same emotion displayed on non-peers’ compared to peers’ faces may have different implications and meanings to the perceiver.

Previous studies investigating the advantage of emotional expressions in visual processing in preschool children only used adult faces. However, children perceive facial expression of emotions differently when displayed on adults’ compared to children’s faces. In the present study, pre-schoolers (N=43, Mean age=5.65) and adults (N=37, Mean age=21.8) had to find a target face displaying an emotional expression among eight neutral faces. Gender of the faces (boy and girl) were also manipulated. Happy faces were found the fastest across both samples. Children detected the angry face faster than the fearful one, while adults vice versa. However, an interaction in the adult sample suggests that this is only true for girls’ faces, while the difference was nonsignificant for boys’ faces. In both samples, the detection was faster with boys’ faces compare to girls’ for all emotions. It is suggested that the happy face could have an advantage in visual processing due to its importance in social situations.