Many faces of expertise: fusiform face area in chess experts and novices

Abstract

The fusiform face area (FFA) is involved in face perception to such an extent that some claim it is a brain module for faces exclusively. The other possibility is that FFA is modulated by experience in individuation in any visual domain, not only faces. Here we test this latter FFA expertise hypothesis using the game of chess as a domain of investigation. We exploited the characteristic of chess, which features multiple objects forming meaningful spatial relations. In three experiments, we show that FFA activity is related to stimulus properties and not to chess skill directly. In all chess and non-chess tasks, experts' FFA was more activated than that of novices' only when they dealt with naturalistic full-board chess positions. When common spatial relationships formed by chess objects in chess positions were randomly disturbed, FFA was again differentially active only in experts, regardless of the actual task. Our experiments show that FFA contributes to the holistic processing of domain-specific multipart stimuli in chess experts. This suggests that FFA may not only mediate human expertise in face recognition but, supporting the expertise hypothesis, may mediate the automatic holistic processing of any highly familiar multipart visual input.

Figure 1.

Experiment 1: stimuli, design, fMRI, and behavioral results. A, Pictures of chess positions or student faces were presented upright or inverted. Participants had to indicate whether the currently presented stimulus matched previously presented stimulus (one-back task). B, Diagram depicting the trial structure in experiment 1. There were two classes of stimuli (chess and faces) and two locations (upright and inverted), for a total of four conditions. All four conditions were presented in each of the three runs four times (12 blocks of each condition in all runs). Blocks included five stimuli (S1–S5), each lasting 1.75 s with a 0.25 s gap between them. C, Time (in seconds) experts and novices needed to match face and chess stimuli when they were presented upright or inverted in experiment 1. RT, Reaction time. D, Activation levels (percentage signal change relative to baseline) in the right FFA in experts and novices on the chess and face stimuli depending on the location in experiment 1. Error bars indicate SEM.

Figure 2.

Experiment 2: stimuli, design, fMRI, and behavioral results. A, The chess stimuli and tasks used in experiment 2. Participants had to indicate whether the white king was in check in the Check task, whether there were knights of both colors presented in the Knight task, and whether two dots (black and white) were present in the Control (dot) task. In all three tasks, there were two types of positions: normal (taken from chess games of masters) and random (pieces were randomly distributed on the board). B, Diagram depicting the trial structure in experiment 2. We first presented a baseline (a starting board with all pieces at their initial location with a fixating cross) in which duration was jittered (6–10 s). After a short gap (0.5 s), the target stimulus was presented, which lasted until the press. S1–S5, First through fifth stimulus. C, Time (in seconds) experts and novices took to complete the check, knight, and control (dot) tasks, depending on the type of position in experiment 2. RT, Reaction time. D, Activation levels (percentage signal change relative to baseline) in the right FFA in experts and novices when executing the check, knight, and control (dot) tasks depending on the type of position in experiment 2. Error bars indicate SEM.

Figure 3.

Experiment 3: stimuli, design, fMRI, and behavioral results. A, The chess stimuli and tasks used in experiment 3. Participants had to count the number of times black could take white pieces in the threats task, the number of knights and bishops in the knights and bishops task, and the number of all pieces on the board in the control (all) task. In all three tasks there were two types of positions: normal (taken from chess games of masters) and random (pieces were randomly distributed on the board). B, Diagram depicting the trial structure in experiment 3. The baseline stimulus was an initial chess board configuration with a fixation cross; its duration was jittered. A gap in stimulus presentation was used as a warning about the upcoming stimulus. The actual chess stimulus (normal and random positions) was then presented. After the players indicated their answers by pressing one of the response buttons, the baseline stimulus of the next trial was presented. C, Time (in seconds) experts and novices took to complete the threats, knights and bishops, and control tasks depending on the type of position in experiment 3. RT, Reaction time. D, Activation levels (percentage signal change relative to baseline) in the right FFA in experts and novices when completing the threats, knights and bishops, and control tasks depending on the type of position in experiment 3. Error bars indicate SEM.