Genetic Influence on Eye Movements to Complex Scenes at Short Timescales

Abstract

Summary Where one looks within their environment constrains one’s visual experiences, directly affects cognitive, emotional, and social processing [1–4], influences learning opportunities [5], and ultimately shapes one’s developmental path. While there is a high degree of similarity across individuals with regard to which features of a scene are fixated [6–8], large individual differences are also present, especially in disorders of development [9–13], and clarifying the origins of these differences are essential to understand the processes by which individuals develop within the complex environments in which they exist and interact. Toward this end, a recent paper [14] found that ‘social visual engagement’ – namely, gaze to eyes and mouths of faces – is strongly influenced by genetic factors. However, whether genetic factors influence gaze to complex visual scenes more broadly, impacting how both social and non-social scene content are fixated, as well as general visual exploration strategies, has yet to be determined. Using a behavioral genetic approach and eye tracking data from a large sample of 11-year-old human twins (233 same-sex twin pairs; 51% monozygotic/49% dizygotic), we demonstrate that genetic factors do indeed contribute strongly to eye movement patterns, influencing both one’s general tendency for visual exploration of scene content, as well as the precise moment-to-moment spatiotemporal pattern of fixations during viewing of complex social and non-social scenes alike. This study adds to a now growing set of results that together illustrate how genetics may broadly influence the process by which individuals actively shape and create their own visual experiences.

Individual differences in visual salience vary along semantic dimensions

“…But it probably also reflects a deep-rooted neurobiological basis of these biases. This possibility is underscored by earlier studies showing that the visual salience of social stimuli is reduced in individuals with autism spectrum disorder 27,38,39 and most importantly by recent twin studies, showing that individual differences in gaze traces are heritable 27,28 . The gaze trace dissimilarities investigated in these studies probably are a manifestation of the salience biases we found here.…”

“…However, even the earliest studies of fixation behaviour noted considerable individual differences 19,20 , and basic occulomotor traits vary reliably between observers [21][22][23][24][25][26] . Recent twinstudies revealed that social attention and gaze traces across complex scenes are highly heritable 27,28 . This suggests individual differences in fixation behaviour are not random, but systematic.…”

Out of mind, out of sight? Investigating abnormal face scanning in autism spectrum disorder using gaze‐contingent paradigm

“…We further calculated the eye movement entropy as an index to quantify how strategical children with ASD was to process human faces compared to TD children. First, each valid trial duration heatmap was produced by smoothing gaze data using a 2° full width at half maximum (FWHM) Gaussian kernel spatial filter (Kennedy et al, ). For each child, their all valid trial smoothed duration heatmaps were averaged together to produce two mean heatmaps (one for each condition).…”

“…For each child, their all valid trial smoothed duration heatmaps were averaged together to produce two mean heatmaps (one for each condition). Then, Shannon entropy was calculated on the mean heatmaps (Gu et al, ; Kennedy et al, ). Entropy provides a measure of statistical randomness or agglomeration of the participants’ eye movements, such that spatially diffused gaze would result in higher entropy values, and spatially tightly focused gaze would result in lower entropy values (Figures and in the supplementary material).…”

“…Finally, to further understand face scanning strategy in children with ASD, we calculated eye movement entropy based on the participants’ gaze data to measure the statistical randomness of the eye movements (Gu, Jin, Dong, & Chang, ; Kennedy et al, ). It is assumed that participants’ eye movement entropy decreased when the environment is perceived as meaningful (Jordan & Slater, ).…”