STUDY 2: LOCATING SUPER RECOGNITION WITHIN THEORETICAL

A second investigation examined processing at theoretically relevant stages of the dominant cognitive model of face-processing proposed by Bruce and Young (1986; see Figure 1). First, we examined facial identity perception skills. Given this process can be

differentially affected in prosopagnosia (Darymple, Garrido, & Duchaine, 2014), we sought to further explore this issue. Second, we examined whether non-identity facial perception is also enhanced in super recognition, and, following the theoretical precedent of the prosopagnosia literature (Duchaine, Parker, & Nakayama, 2003; Duchaine, Yovel, Butterworth, & Nakayama, 2006), focus this investigation on the recognition of facial expression. Performance on each process is examined using two different tests, to allow a more conservative assessment of the cognitive presentation of each participant.

4.1. Perception of facial identity

CFPT (Duchaine et al., 2007): This test requires participants to arrange six faces displayed from a frontal viewpoint in order of their similarity to a target face that is presented in a three-quarter viewpoint. The six test faces were created by morphing target faces with distractor faces. Participants complete 16 trials in total: eight with the faces upright and the remainder in an inverted format. Performance on the CFPT is measured as the total number of errors (i.e., how far away the participant is from a perfect arrangement), so that a lower score reflects better performance. Because there is some variability in the scores achieved by typical participants on the CFPT (Bowles et al., 2009), control data was collected from a larger sample of controls (N = 58, see Table 3). Nevertheless, the standard deviation for our sample was still relatively large (as observed in previous work, Russell et al., 2012), preventing any single-case analyses on the upright condition from reaching significance (all ps > .17)³. It is of note, though, that all participants bar one (CH) outperformed controls by at least one standard deviation. Further,

3 Analysis of the inverted condition on this test is presented in the discussion of configural/holistic processing below (see section 5.4).

Table 3. Results from the tasks administered in Study 2. All values for SR participants are expressed in the number of SDs away from the control mean.

Controls Super-Recognisers

Mean SD N CH DF JN GK CW TP

Perception of facial identity

Matching test (upright faces, d’): 2.00 0.40 21 1.60 2.90* 3.30* 0.10 1.10 1.80 CFPT^a:

Upright 35.90 15.00 58 -0.70 -1.60 -1.10 -1.30 -1.30 -1.10

Inverted 61.80 11.40 58 0.60 -1.20 0.20 -1.60 -0.30 -1.70

Perception of facial expression

Ekman 60^b 51.7/60 4.2 30 -0.60 0.80 0.80 -1.10 0.30 0.80

Mind in the Eyes accuracy^c 27.6/36 4.0 29 -0.20 0.60 0.10 -0.40 1.40 0.90

Mind in the Eyes RT 7001.19 1872.57 28 -0.69 0.02 0.31 -0.44 -1.00 1.13

General socio-emotional functioning EQ^d:

Females 50.6/80 9.20 - - - 0.70 - - -

Males 41.3/80 10.10 - 0.50 1.00 - 2.50* -0.90 0.50

* indicates participant significantly differed to controls using Crawford et al.’s (2010) modified t-tests for single-case comparisons ( p < .05)

aCambridge Face Perception Test (Duchaine et al., 2007), lower score indicates better performance; ^bEkman 60 faces test (Young et al., 2002); ^cReading the Mind in the Eyes (Baron-Cohen et al., 2001); ^dEmpathy Quotient (test and norms from Lawrence et al. (2004) – separate norms are provided for male and female participants.

the scores that were achieved are similar to those reported by Russell et al. (2009), which were significantly better than controls in a group-based analysis.

Matching test: Given the statistical difficulties in identifying superior performance on the CFPT, we further assessed face perception skills by considering performance in the

“upright face” condition of our matching task described above (see section 3.1 and Table 2). On this task, two of the SRs – JN and DF – showed an exceptional ability to match upright faces compared to controls. Pertinently, DF also achieved the most proficient score on the upright condition of the CFPT.

4.2. Perception of emotional expression

Ekman 60 faces (Young, Perrett, Calder, Sprengelmeyer, & Ekman, 2002): In this task participants have to label pictures of actors with one of six emotions: anger, happiness, sadness, fear, surprise, or disgust. The emotions are presented by ten actors (four male and six female) and displayed on screen for five seconds. Participants indicate their response by a mouse click on the relevant tab describing the emotion. Single-case comparisons showed no significant differences between any SR and the control group on this test (all ps

> .1), and no individual SR performed above one standard deviation of the control mean (see Table 3). No reaction time data was available for analysis on this test.

Reading the Mind in the Eyes Test (RMITE: Baron-Cohen, Wheelwright, Hill, Raste, &

Plumb, 2001). In the RMITE test, participants are presented with 36 images of the eye region of actors (males and females) and provided with a description of four mental states to choose from. Unlike the Ekman 60 faces task which exposes participants to six basic emotional states, the emotion descriptions in this test differ very subtly from one another.

Images are presented on screen for an unlimited amount of time and responses are elicited

by a key press. Again, single-case comparisons showed no significant differences between any SR and the control group (all ps > .1).

Because accuracy was high on this test, we additionally examined the speed of participants’ responses. None of the SRs performed significantly faster on this test, and it is of note that the SR (CW) who performed most accurately was one SD slower than controls. However, the RMITE test does not impose a time constraint on participants and it is possible that CW engaged in a more effortful analysis of the stimuli. Nevertheless, there is little evidence to suggest that superior face recognition is also accompanied by enhancements in facial expression recognition.

Empathy Quotient (EQ: Lawrence, Shaw, Baker, Baron-Cohen, & David, 2004): Finally, we also collected a brief self-report measure of socio-emotional functioning in the SR group. Previous work indicates that, in the typical population, higher scores on the EQ are associated with more advanced face recognition skills (Bate et al., 2010), indicating that enhanced socio-emotional rather than visuo-cognitive processes may sometimes contribute to face recognition performance. Importantly, the EQ does not measure socio-emotional functioning using facial stimuli, but consists of 60 self-report questions. Forty items tap into participant’s level of empathy, whereas 20 filler items (which are not analysed) are included in the scale to distract participants from a continuous focus on empathy. There are four response options, and the test has a maximum score of 80. TP, CH, JN, CW and DF performed within one standard deviation of the control norm on this test (see Table 3). One SR, GK, achieved a score significantly higher than the gender-relevant control norm, t(24)

= 2.88, p = .008, Zcc = 2.941, 95% CI [2.020, 3.849]; estimated % population below his score = 99.59. Interestingly, however, this individual achieved scores that were lower than the control mean on both the Ekman 60 Faces and RMITE tests. Hence, enhanced

socio-emotional processing does not seem to boost the recognition of facial socio-emotional expression in GK, although it is possible that it may underpin this individual’s superior facial identity recognition skills.

4.3. Summary of Study 2

This is the first study to examine whether SRs excel at the perception of facial information other than identity. The results suggest that, at least in comparison to the perception of emotional expression, SRs’ abilities are specific to identity-based tasks. These findings argue against the idea that SRs are better at extracting information from faces in general – instead, it appears that SRs are particularly adept at extracting and/or using facial identity information.