Faces strongly attract early fixations in naturally sampled real-world stimulus materials

Abstract

Faces are an important and salient stimulus in our everyday life. They convey social information and, consequently, attract our attention easily. Here, we investigate this face-attraction-bias in detail and analyze the first fixations made in a free-viewing paradigm. We presented 20 participants with natural, head-centered, live-sized stimuli of indoor scenes, taken during unconstrained free-viewing in a real-world environment. About 70% of first fixations were made on human faces, rather than human heads, non-human faces or the background. This effect was present even though human faces constituted only about 5% of the stimulus area and occurred in a wide variety of positions. With a hierarchical logistic model, we identify behavioral and stimulus’ features that explain this bias. We conclude that the face-attraction bias replicates under more natural conditions, reflects high-level properties of faces, and discuss its implications on the measurement of brain dynamics.