Data from: Two sources of bias explain errors in facial age estimation

Accurate age estimates underpin our everyday social interactions, the
provision of age-restricted services and police investigations. Previous
work suggests that these judgments are error-prone, but the processes
giving rise to these errors are not understood. Here we present the first
systematic test of bias in age estimation using a large database of
standardized passport images of heterogeneous ages (n = 3948). In three
experiments we tested a range of perceiver age groups (n = 84), and found
average age estimation error to be approximately 8 years. We show that
this error can be attributed to two separable sources of bias. First, and
accounting for the vast majority of variance, our results show an
assimilative serial dependency whereby estimates are systematically biased
towards the age of the preceding face. Second, younger faces are generally
perceived to be older than they are, and older faces to be younger. In
combination, these biases account for around 95% of variance in age
estimates. We conclude that that perception of age is modulated by
representations that encode both a viewer’s recent and normative exposure
to faces. The finding that age perception is subject to strong top-down
influences based on our immediate experience has implications for our
understanding of perceptual processes involved in face perception, and for
improving accuracy of age estimation in important real world tasks.