Sensorimotor experience biases human attention through space and time

Space and time are fundamental dimensions that contribute to make human minds grounded in the physical world. Researchers across the cognitive sciences have recently addressed some key questions about the role of the sensorimotor system in spatial and temporal processing (Chapter 1). The present thesis adds to this debate by exploring the hypothesis that prior directional sensorimotor experience contributes to the human sense of space and time. The first part of the thesis investigates whether sensorimotor experience influences visuospatial attention. A first study shows that humans have a manual and ocular leftward bias in bisection task in near but not in far space (Chapter 2). This leftward bias, for long mainly explained in terms of a right hemispheric dominance in visuospatial processing, is modulated by directional routines. For instance, individuals from different cultures show visuospatial asymmetries that can predicted by their reading habits (Chapter 3). Similarly, exposure to formal education exerts a strong influence on children’s visuospatial attention (Chapter 4). Nonetheless, the impact of cultural routines is further constrained by situational requirements. In fact, bidirectional readers reorient their visual scanning depending on the language of the task at hand (Chapter 5). In line with this, visuospatial biases can be rapidly induced by learned contingent odor-object associations (Chapter 6). On these grounds, it is therefore suggested that biological factors (i.e., hemispheric specialization) interplay with both cultural (i.e., directional scanning associated with language processing) and situational factors (i.e., current constraints imposed by task demands) in modulating visuospatial attention, likely under a hierarchical relationship (Chapter 7). Since space and time are supposed to be tightly coupled in the human mind by motor actions, the second part of the thesis investigates whether sensorimotor experience influences the spatial representation of time. A first study shows that both finger counting and reading habits are flexibly exploited to map ordered information on the bodily space (Chapter 8). The sensorimotor involvement in representational processes was confirmed in a study showing that eye movements mediate the search and the retrieval of temporally ordered information (Chapter 9). In addition, the view that the egocentric representation of time originates from our walking experience was empirically supported by showing that temporal processing affects step movements along the sagittal space (Chapter 10). Finally, the systematic tendency to experience the future as psychologically closer than the past, derived from our experiential movement through time, was found to be altered in people with slower walking speed and distorted motion perception, i.e., anxious and depressed individuals. (Chapter 11). These studies, therefore, suggest that the processing of time is governed by the same mechanisms that orient our attention in the physical space (Chapter 12). Overall, this thesis indicates that prior sensorimotor experience affects the way humans attend to space and time (Chapter 13).