Realism Matters. Eye movements in VR reveal prior tool knowledge, intended interaction, and end-state comfort planning

Abstract

AO_SCPLOWBSTRACTC_SCPLOWSeminal studies on human cognitive behavior have been conducted in controlled laboratory settings, demonstrating that visual attention is mainly goal-directed and allocated based on the action performed. However, it is unclear how far these results generalize to cognition in more naturalistic settings. The present study investigates active inference processes revealed by eye movements during interaction with familiar and novel tools with two levels of realism of the action affordance. We presented participants with 3D tool models that were either familiar or unfamiliar, oriented congruent or incongruent to their handedness, and asked participants to interact with them by lifting or using. Importantly, we used the same experimental design in two setups. In the first experiment, participants interacted with a VR controller in a low realism environment; in the second, they performed the task with an interaction setup that allowed differentiated hand and finger movements in a high realism environment. We investigated the differences in odds of fixations and their eccentricity towards the tool parts before action initiation. The results show that participants fixate more on the tools effector part before action initiation for the use task for unfamiliar tools. Furthermore, with more realistic action affordances, subjects fixate more on the tools handle as a function of the tools orientation, well before the action was executed. Secondly, the spatial viewing bias on the tool reveals early fixations are influenced by the task and the familiarity of the tools. In contrast, later fixations are associated with the manual planning of the interaction. In sum, the findings from the experiments suggest that fixations are made in a task-oriented way to plan the intended action well before action initiation. Further, with more realistic action affordances, fixations are made towards the proximal goal of optimally planning the grasp even though the perceived action on the tools is identical for both experimental setups. Taken together, proximal and distal goal-oriented planning is contextualized to the realism of action/interaction afforded by an environment.