Abstract
Evidence suggests that adults perceive male faces more negatively than female faces, an angry-male/happy-female bias (e.g., Becker et al., 2007; Harris et al, 2016; Korb & Massaccesi, 2020). We considered how such biases change across development. We recruited 394 children (6-18 year-olds) and 38 adults (18-35 year-olds) at the Museum of Science, Boston, Massachusetts. Participants viewed four face identities (2F, 2M), each morphed along a happy-angry continuum, (10, 40, and 80% happy and the complementary angry), for a total of 24 face morphs. Trials started with a fixation cross at screen center (1sec), followed by a single face morph (1sec), and then a question mark (6sec), during which participants judged the emotion of the face as either happy or angry via button press. To quantify perceptual bias, at a given age we fit group data with a cumulative normal, for male and female faces separately, and calculated the point of subjective equality (PSE), or the face equally likely to be judged happy as angry. Considering the role of experience in forming biases, such as increased exposure to aggressive behaviors during school years, especially from male classmates (Chapell et al., 2006), we expected the angry-male/happy-female bias to increase with age, as measured by the difference in PSE for male vs female faces. Specifically, we expected the angry-male bias to increase with age, with no explicit predictions for changes in the happy-female bias with age. Contrary to our expectations, we found an overall decrease in the angry-male/happy-female bias with age. Older children and adults had a less positive PSE for male faces, a less negative perceptual bias, and a more positive PSE for female faces, a more negative perceptual bias. Future work will need to tease apart the select experiences that may contribute to such biases early in development.