The Oxford Face Matching Test: A Non-Biased Test of The Full Range of Individual Differences in Face Perception

Abstract

Tests of face processing are typically designed to identify individuals performing outside of the typical range; either prosopagnosic individuals who exhibit poor face processing ability, or super recognisers, who have superior face processing abilities. Here we describe the development of the Oxford Face Matching Test (OFMT), designed to identify individual differences in face processing across the full range of performance, from prosopagnosia, through the range of typical performance, to super recognisers. Such a test requires items of varying difficulty, but establishing difficulty is problematic when particular populations (e.g. prosopagnosics, individuals with Autism Spectrum Disorder) may use atypical strategies to process faces. If item difficulty is calibrated on neurotypical individuals, then the test may be poorly calibrated for atypical groups, and vice versa. To obtain items of varying difficulty we used facial recognition algorithms to obtain face pair similarity ratings that are not biased towards specific populations. These face pairs were used as stimuli in the OFMT, and participants required to judge if the face images depicted the same individual or different individuals. Across five studies the OFMT was shown to be sensitive to individual differences in the typical population, and in groups of both prosopagnosic individuals and super recognisers. The test-retest reliability of the task was at least equivalent to the Cambridge Face Memory Test and the Glasgow Face Matching Test. Furthermore, results reveal, at least at the group level, that both face perception and face memory are poor in those with prosopagnosia, and good in super recognisers.

Use of the Oxford face matching test reveals an effect of ageing on face perception but not face memory

“…Scores can range from 0 to 200. OFMT scores were previously shown to be reliable (correlation between tests r = .75 over a 2-weeks delay; Stantić et al, 2021a). See Figure 1A for a sample trial.…”

“…Given the possibility of a change in how faces are processed with age, it is of particular importance that a sensitive and unbiased test is used to compare the face perception of older and younger adults. We suggest that using the recently developed Oxford Face Matching Test (OFMT; Stantić et al, 2021a) in an ageing population could assist in answering many of the outstanding questions raised above.…”

“…The OFMT aims to overcome this problem by using ratings of face similarity from three facial recognition algorithms when calibrating stimulus difficulty. Pairs of face images from the same person, or from different people, are rated for their similarity by the algorithms (see Stantić et al, 2021a). When the algorithms all agree, the algorithmic judgements of facial similarity are used to create trials of varying difficulty where very similar facial images from the same people, and very different images from different people, are easy to correctly judge as from the same individual or not.…”

“…Conversely, very different facial images from the same person, and very similar facial images from different people constitute difficult trials. In addition to standard tests of validity and reliability, the OFMT has been used to demonstrate altered face perception in both those with very poor face memory (developmental prosopagnosics) and those with very good face memory (super recognisers; Stantić et al, 2021a). It was also recently used to investigate face perception in individuals with Autism Spectrum Disorder (Stantić, Ichijo, Catmur, & Bird, 2021b), due to research reporting that autistic individuals are more likely to process faces in a piecemeal, featural fashion, rather than holistically like neurotypical individuals (Gauthier, Klaiman, & Schultz, 2009;Teunisse & de Gelder, 2003; although see e.g., Nishimura, Rutherford, & Maurer, 2008;Brewer, Bird, Grey, & Cook, 2019;Ventura et al, 2018).…”

“…The Oxford Face Matching Test (OFMT) (Stantić et al, 2021a) On each trial of the OFMT participants have to indicate whether two faces presented for 1600ms are of the same individual or different individuals, as well as how similar the faces are on a scale from 1 (very dissimilar) to 100 (very similar). There is no time limit to respond.…”