Despite the injunction "Don't judge a book by its cover," considerable research demonstrates that people have a strong tendency to use facial appearance when forming first impressions of others' psychological traits, and that these impressions show considerable consensus across perceivers.

With the retirement of Professor Zebrowitz in August 2020, the Zebrowitz Face Perception Lab has closed after many years of research that took a functional approach to social perception, assuming that social perceptions based on appearance either should be accurate or should reflect perceptual biases that serve some general adaptive function. Numerous publications have supported the hypothesis that the evolutionary and social importance of detecting attributes like emotion, age, identity or fitness has created a strong tendency to respond to the facial qualities that reveal these attributes, and that this tendency is overgeneralized to people whose faces merely resemble a particular emotion, age, identity or level of fitness.

This research program addressed four basic questions:

  1. What are the facial qualities that influence trait impressions?
  2. Why do perceivers respond as they do to these particular facial qualities?
  3. What are the social and psychological consequences of judging others by their appearance?
  4. How do these responses change across the life span?

Research investigating these questions has included laboratory experiments, field studies, and secondary analyses of longitudinal data bases.

Research also has investigated the ability of connectionist modeling to predict trait impressions of faces, based on an artificial neural network's tendency to confuse those faces with others that actually do have the traits.

Research has further used fMRI to identify brain mechanisms involved in perceiving traits in faces.