Abstract

A person’s appearance contains a wealth of information. Based on appearance we form first impressions that can set the tone of subsequent relationships. It’s crucial we form an accurate initial impression, but previous work suggests these judgements are error-prone. Prior expectation can bias our decisions: Studies have reported biases to respond ‘‘male’’ when asked to report a person’s sex from an image of their face and to place their age closer to their own. Perceptual expectation effects and cognitive response biases may both contribute to these inaccuracies. I will present research using a Bayesian modelling approach to establish the perceptual biases involved when estimating the sex and age of an individual from their face. This research suggests the well-established male bias is perceptual in origin and may be impervious to cognitive control. In comparison, the own age anchor effect is not operationalized at the perceptual level. In addition, age estimates are systematically biased towards the age of a preceding face. Based on the results of our Bayesian modelling approach to facial appearance, distinct biases in the estimation of facial appearance operate at the perceptual and cognitive levels.