Supplemental Materials
Individual Differences in Adaptive Coding of Face Identity Are Linked to Individual
Differences in Face Recognition Ability by G. Rhodes et al., 2014, JEP: Human Perception and Performance http://dx.doi.org/10.1037/a0035939
Task Details
Face Identity Aftereffects Task
Stimuli
. Grayscale photographs of four male faces comprised the targets (“Dan,” “Jim,”
“Rob,” and “Ted”; taken from Jeffery et al., 2011). Reduced strength versions were made by morphing each face toward an average face (constructed from 20 adult male faces) using
Gryphon Morph 2.5 (Maxwell, 1994), in varying increments to produce 15%, 30%, and 90% versions of each target. The 100% and 30% stimuli were used only in training and the 90% and
15% stimuli were used as test faces (see Figure 1). Adapting antifaces were made by caricaturing the form of the average male away from each target face by 80% (after Leopold, O'Toole, Vetter,
& Blanz, 2001) using Gryphon Morph 2.5 (Maxwell, 1994). To minimize non-facial cues stimuli were masked so that the top of the hairline was obscured. Adapting faces subtended an average visual angle of 5.5° (v) x 5.6° (h), viewed from approximately 65 cm. Test faces were 20% smaller, to minimise the impact of low-level adaptation, measuring 4.8° (v) X 4.5° (h).
Procedure. The task was presented as the “Robbers Game,” following Jeffery et al
(2011). The game context was devised for use with children but has also proved an engaging way to present the task to adults (Jeffery et al, 2011, 2013). Participants began with training in recognizing the targets (100% versions) and familiarization with lower strength versions of the targets (30% versions), who were introduced as the brothers of each target. Participants were told to respond with the team leader’s name (target) whenever they saw the target or a member of his team (his brothers). Participants responded using labeled keyboard keys. Auditory feedback
(beeps) was provided for correct and incorrect responses throughout training.

Figure S1 . Face stimuli used in the identity aftereffect task. The first row shows the four target identities “Dan,” “Jim,” “Rob,” and “Ted” (l-r). Rows 2, 3, and 4 show weaker versions of the targets used in training and test. Row 5 shows the adapting antifaces.
Participants then completed the adaptation task. The experimenter explained that a robber’s face (adapting antiface) would appear on the screen, “while he was stealing things,” and then it would disappear and be followed by a very brief presentation of the face of the team member (test stimulus) who caught the robber. The participant was asked to identify the catcher’s team. The task comprised 96 trials. The 15% stimuli were the test faces on 64 trials, which comprised 32 match trials, in which the adapting antiface and test face lay on the same identity trajectory and 32 mismatch trials in which the adapt and test face came from different

identity trajectories (see Figure 2). Each target was shown equally often in each condition (i.e. 8 trials per target). The remaining 32 trials featured 90% targets as test faces (16 match and 16 mismatch trials). These easy-to-identify stimuli were included to ensure participants remained motivated throughout the task and data from these trials were not analyzed.
Each trial began with blank grey screen (300 ms) then the adapting faces was shown
(5000 ms), followed by a 150 ms inter-stimulus interval, then the test face (400 ms). A blank screen followed and remained until the participant responded. Following response, participants initiated the next trial by pressing the spacebar. Trial sequence is shown in Figure S2. Trials were presented in one of two pseudorandom orders, constrained so that the same adapting face did not appear more than four times consecutively, to avoid building up adaptation to one face.
Participants were randomly allocated to one order. The 96 trials were divided into eight blocks of
12 trials. Half the trials were completed in the first test session and the remainder in the week following (second session). Training was completed prior to the adaptation task on both days.
The experimenter observed each participant to ensure they looked at the adapting faces for the full presentation.

Figure S2 . Example match and mismatch trial sequence and timings in the Face Identity
Aftereffect Task (adapted from Jeffery et al, 2011).
Old–New Recognition of Own-Race and Other-Race Faces
This was a standard old–new recognition task using Asian and Caucasian faces. It took approximately 30 min to complete.
Stimuli. Study faces were front-views of 30 Caucasian and 30 Asian faces. Test faces consisted of the study faces photographed at 3/4 view, as well as an 30 3/4 view distractors for each race. All faces were male and displaying a neutral expression. Caucasian face stimuli were obtained from Christian Meissner and Asian face stimuli were obtained from William Hayward.
To minimize the use of non-face cues, the hair (including forehead hairline) was masked. Study faces measured approximately 5.9° x 5.3° (Asian), and 6.0° x 5.3 (Caucasian), and test faces measured 6.5° x 5.5° (h) (Asian), and 6.8° x 5.7° (h) (Caucasian), when viewed from 60 cm.
Procedure. Participants were verbally informed that they would see 10 faces consecutively, which they must try to remember, and that once they have seen all 10 faces, they would see the faces a second time to enhance their memory. Participants were instructed that once this study phase was over, they would then be shown a bigger group of faces, one at a time, to which they must indicate whether the face was “old” or “new.” Participants were told that this study-test sequence would occur six times. Instructions were also presented on screen prior to beginning the task.
Study faces were presented for 3000 ms followed by a 500 ms ISI. Once the series of 10 faces was shown, an instruction screen was displayed asking participants to press the spacebar to see the faces again. After the series of faces was repeated, participants were given one minute to work on a number sleuth puzzle. Following this was the test phase. Each test trial began with a
3/4 view test face presented for 5000 ms, followed by a screen featuring the wording, “Did you see this face in the previous study phase?”. The participant’s response triggered the next trial to begin. There were 20 trials in each test block. Faces were blocked by race, with race alternating across study-test blocks and race of the first block counterbalanced across participants. Study faces were allocated to study blocks in a fixed random order. Trial order was randomized within study and test blocks.

Jeffery, L., Rhodes, G., McKone, E., Pellicano, E., Crookes, K., & Taylor, E. (2011).
Distinguishing norm-based from exemplar-based coding of identity in children: Evidence from face identity aftereffects. Journal of Experimental Psychology: Human Perception and
Performance , 37 , 1824–1840. doi: 10.1037/a0025643
Leopold, D. A., O'Toole, A. J., Vetter, T., & Blanz, V. (2001). Prototype-referenced shape encoding revealed by high-level aftereffects. Nature Neuroscience , 4 , 89–94. doi:
10.1038/82947
Maxwell, D. (1994). Gryphon Morph (Version 2.5): Gryphon Software Corporation.