Effects of Social and Non-Social Interpretations of Complex Images on Human Eye Movement and Brain Activation

Communicating and interacting with others is an essential part of our daily routines as humans. Performing these actions appropriately requires the ability to identify, extract, and process salient social cues from the environment. The subsequent application of such knowledge is important for inferring and predicting the behavior of other people. The eyes and brain must work together to fixate and process only the most critical social signals within a scene while passing over and / or completely ignoring other aspects of the scene. While brain activation to isolated presentations of objects and people presentations have been characterized, information about the brain's activation patterns to more comprehensive scenes containing multiple categories of information is limited. Furthermore, little is known about how different interpretations of a scene might alter how that scene is viewed or how the brain responds to that scene. Therefore, the studies presented herein used a combination of infrared eye tracking and functional magnetic resonance imaging techniques to investigate the eye movement and brain activation patterns to socially- and non-socially-relevant interpretations of the same set of complex stimuli. Eye tracking data showed that each gaze pattern was consistent with viewing and attending to only one category of information (people or objects) despite both categories being present in all images. Functional magnetic resonance imaging revealed that a region of the right superior temporal sulcus was selectively activated by the social condition compared to the non-social condition, an area known for its role in social tasks. Brain activation in response to the non-social condition was located in many of the same regions associated with the recognition and processing of visual objects presented in isolation. Taken together, these results demonstrate that in healthy adults, eye movement and brain activation patterns to identical scenes change markedly as a function of attentional focus and interpretation intention. Utilizing realistic and complex stimuli to study the eye gaze and neural activation patterns associated with processing social versus non-social information in the healthy brain is an important step towards understanding the deficits present in individuals with social cognition disorders like autism and schizophrenia.