On the Complexity of Visual Judgement of Kinship.

Linda Brodo,Enrico Grosso

doi:10.1177/2041669519841642

Abstract

Discrimination of close relatives is a basic ability of humans, with demonstrated and important consequences in social and sexual behaviours. In this article, we investigate the visual judgement of kinship, that is the process of discriminating relatives based on visual cues and, in particular, on facial resemblance. Starting from triplets of face stimuli, we focus on a simple two-alternative forced choice protocol and we ask participants to evaluate kinship, similarity, or dissimilarity. Response times of the participants performing these visual judgements are recorded and further analysed. The analysis can also benefit from previous findings on the adopted face data set; in particular, results are compared with reference to an independently generated and statistically reliable similarity index, which is available for each possible considered pair of images. Our results confirm previous findings stating that kinship and similarity judgements are closely related and take longer, on average, than dissimilarity judgement. Moreover, they confirm that similarity and dissimilarity cannot be considered just as opposite concepts, and strongly support the existence of different pathways for similarity and dissimilarity judgements. Concerning kinship judgements, results confirm the assumption, inherent in previous models, of a close relationship between cues signalling for kinship and cues signalling for similarity but suggest the existence of a more complex process, where dissimilarity cues need to be explicitly included in order to model measured effects. Our results reinforce the idea that modulation mechanisms between similarity and dissimilarity measures could explain selective suppression or enhancement effects reported in previous works. A new framework is thus proposed hypothesising that kinship recognition is the result of a balanced evaluation of both similar or dissimilar pathways.

Highlights

In recent years, research on face perception led to remarkable advances in the understanding of many different aspects of how faces are processed and memorised by the human brain (Little, Jones, & DeBruine, 2011)
The results of the main experiment confirm and extend previous results, providing additional insights concerning the relation between kinship, similarity, and dissimilarity judgements
A first important statement concerns the general timing of the judgements involved: as reported in Lorusso et al (2011), Task D is always the fastest one and Task K is always the slowest

Summary

Introduction

Research on face perception led to remarkable advances in the understanding of many different aspects of how faces are processed and memorised by the human brain (Little, Jones, & DeBruine, 2011). We focus on a specific and fundamental feature of face perception, that is the ability to recognise kinship from visual cues This problem has been studied in the last decade (Dal Martello & Maloney, 2006; DeBruine et al, 2009; Lorusso, Brelstaff, Brodo, Lagorio, & Grosso, 2011) partly confirming the anecdotal belief of a close relation between facial resemblance and kinship perception. Humans can reliably detect close relatives with respect to themselves and between other individuals; this peculiar trait has been recently referred as allocentric kin recognition (Dal Martello, DeBruine, & Maloney, 2015)

Methods

Results

Conclusion