Seeing faces where there are none: Pareidolia correlates with age but not autism traits.

Previous research has found that individuals with autism spectrum disorder experience difficulties when visually processing face stimuli compared to developmentally typical individuals. Whether, in the typically-developing population, face detection depends on autism-like traits (ALTs) is less clear. In this report, we aimed to develop an experimental design that is more sensitive to any individual differences in face detection than previous reports. We employed pareidolia, that is, cases where non-face stimuli are perceived to be faces, assuming this is more difficult than detection of 'real' faces, decreasing changes of ceiling performance. We also show multiple faces per trial, allowing for a more graded assessment of face detection ability. Participants were 263 individuals aged between 18 and 82 years of age. Pareidolia was investigated in two online experiments, with different types of stimuli: objects that could be perceived as faces (i.e., embedded faces task) and Mooney faces (Mooney face task). In the latter condition, we also investigated the face inversion effect. We found that neither detection ability or the inversion effect depended on ALTs. We did find a dependence of age for both measures, and a complex dependence on gender for Mooney faces. Our data suggest that face detection (and specifically pareidolia) does not depend on ALTs, but does depend on the age of the observer. The dependence on age appears to be different between the two experiments, suggesting that the underlying mechanisms necessary for face detection in our two experiments mature and decline at different rates.