The sibling familiarity effect: Is within?person facial variability shared across siblings?

Ailsa Strathie,Sarah Laurence,Naomi Hughes‐White

doi:10.1111/bjop.12517

Ailsa Strathie, Sarah Laurence + Show 1 more

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https://doi.org/10.1111/bjop.12517

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Abstract

Humans are experts at familiar face recognition, but poor at unfamiliar face recognition. Familiarity is created when a face is encountered across varied conditions, but the way in which a person's appearance varies is identity?specific, so familiarity with one identity does not benefit recognition of other individuals. However, the faces of biological siblings share structural similarities, so we explored whether the benefits of familiarity are shared across siblings. Results show that familiarity with one half of a sibling pair improves kin detection (experiment 1), and that unfamiliar face matching is more accurate when targets are the siblings of familiar versus unfamiliar individuals (experiment 2). PCA applied to facial images of celebrities and their siblings demonstrates that faces are generally better reconstructed in the principal components of a same?sex sibling than those of an unrelated individual. When we encounter the unfamiliar sibling of someone we already know, our pre?existing representation of their familiar relation may usefully inform processing of the unfamiliar face. This can benefit both kin detection and identity processing, but the benefits are constrained by the degree to which facial variability is shared.

Highlights

How to cite: Strathie, Ailsa; HughesWhite, Naomi and Laurence, Sarah (2021)
There was a significant effect of familiarity [t (36) = 3.08, p = .004, d = 0.51] with higher sensitivity (d) in the familiar condition (M = 0.73, SD = 0.59) than in the unfamiliar condition (M = 0.37, SD = 0.42)
The significant effect of sibling familiarity on sensitivity shows that people are more accurate at deciding whether two people are siblings when one of the targets is familiar versus unfamiliar

Summary

Introduction

How to cite: Strathie, Ailsa; HughesWhite, Naomi and Laurence, Sarah (2021). The sibling familiarity effect: Is withinperson facial variability shared across siblings? British Journal of Psychology (Early Access). When we encounter the unfamiliar sibling of someone we already know, our pre-existing representation of their familiar relation may usefully inform processing of the unfamiliar face This can benefit both kin detection and identity processing, but the benefits are constrained by the degree to which facial variability is shared. Familiar faces can be successfully identified across substantial changes in appearance (e.g., Davies & Milne, 1982; Noyes & Jenkins, 2019; Troje & Kersten, 1999) while even small alterations in pose or camera angle can thwart identification of unfamiliar faces (e.g., Bruce, 1982; Burton, White, & McNeill, 2010; Megreya & Burton, 2006, 2007). The representation of unfamiliar faces is thought to be largely imagedependent (e.g., Bruce, 1982; Bruce & Young, 1986; Hancock, Bruce, & Burton, 2000), while familiar faces have been encountered across changes in lighting, angle, expression, age, hairstyle, etc., creating a robust representation that is largely independent of individual image properties (Andrews, Jenkins, Cursiter, & Burton, 2015; Burton, 2013; Burton, Kramer, Ritchie, & Jenkins, 2016; Dowsett, Sandford, & Burton, 2016; Jenkins, White, Van Montfort, & Burton, 2011; Ritchie & Burton, 2017)

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