Viewers base estimates of face matching accuracy on their own familiarity: Explaining the photo-ID paradox

Abstract

Matching two different images of a face is a very easy task for familiar viewers, but much harder for unfamiliar viewers. Despite this, use of photo-ID is widespread, and people appear not to know how unreliable it is. We present a series of experiments investigating bias both when performing a matching task and when predicting other people's performance. Participants saw pairs of faces and were asked to make a same/different judgement, after which they were asked to predict how well other people, unfamiliar with these faces, would perform. In four experiments we show different groups of participants familiar and unfamiliar faces, manipulating this in different ways: celebrities in experiments 1-3 and personally familiar faces in experiment 4. The results consistently show that people match images of familiar faces more accurately than unfamiliar faces. However, people also reliably predict that the faces they themselves know will be more accurately matched by different viewers. This bias is discussed in the context of current theoretical debates about face recognition, and we suggest that it may underlie the continued use of photo-ID, despite the availability of evidence about its unreliability.

Forming impressions of facial attractiveness is mandatory

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Recognizing Faces

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Not looking yourself: The cost of self‐selecting photographs for identity verification

“…Tests of participants with professional experience in face matching suggest that their performance is no better: Both police officers (Burton, Wilson, Cowan, & Bruce, 1999) and passport officers (White, Kemp, Jenkins, Matheson, & Burton, 2014) show equivalent performance to groups of untrained students. Compounding this problem further, recent work shows that people systematically underestimate the difficulty of unfamiliar face matching decisions when they are themselves familiar with the face (Ritchie et al, 2015). Thus, our experience in recognizing familiar faces may propagate the popular and incorrect belief that photo-ID is a reliable method for identification.…”