Idiosyncratic eye-movement patterns modulate holistic processing of faces: evidence from the composite face effect and the inverted face effect

It is well established that faces are processed holistically, with the face inversion paradigm and the composite face paradigm two being widely used tasks to demonstrate this mode of processing. However, many recent studies have found that individuals differ in their eye movements to faces, and little is known about whether these differences in eye movements modulate holistic processing. To investigate this issue, participants were asked to complete the upright (or inverted) face identification task and the top (or bottom) cued composite face task. Using the Eye Movement analysis with Hidden Markov Models (EMHMM) approach to analyze their eye movements, participants were clustered into two groups on the basis of their eye movement patterns during the upright face identification task, with an upper-focused group who preferred to look at the upper half of a face (such as the eyes), and another lower-focused group who preferred to look at the nose or the mouth of a face. These two groups showed no significant difference in the size of the face inversion effect. But in the composite face task, the upper-focused group showed a stronger composite effect for matching the upper halves of faces than the lower halves, while the lower-focused group had similar magnitudes of composite effect between judging the upper half and the lower half conditions. Thus, holistic face processing is influenced by one's preferred face-scanning pattern.