Faces in the eye of the beholder: unique and stable eye scanning patterns of individual observers.

Eye scanning patterns while viewing pictures have provided valuable information in many domains of visual cognition. Such patterns are determined by the type of image viewed (e.g., faces, scenes) as well as the task individuals are asked to perform (e.g., visual search, memory). Here we show that another key factor that significantly influences eye scanning patterns but has been mostly overlooked is the individual observer. During face viewing, we found that individuals showed diverse scanning patterns that, in many cases, were inconsistent with the typical triangular shape pattern that is commonly observed when eye scanning patterns are averaged across individuals. These idiosyncratic eye scanning patterns were not random but highly stable even when examined 18 months later. Interestingly, these eye-tracking patterns were not predictive of behavioral performance. Such stable and unique scanning patterns may represent a specific behavioral trait/signature and be formed early in development, reflecting idiosyncratic strategies for performing visual recognition tasks.