Abstract
The study of task-switching has a rich history (Monsell, 2003) but has been surprisingly overlooked as it relates to vision. Task-switching studies primarily focus on executive function relating to maximizing performance benefits while minimizing costs. When task-switching has been applied to vision it is usually to investigate the executive function required to switch back and forth between prosaccades and antisaccades as opposed to the influence of a task switch on visual behavior per se. Critically, recent examinations of task set and visual behavior have demonstrated differences in the influence of memory on attentional allocation and the spatial and temporal characteristics of oculomotor kinematics (Dodd et al., 2009; Mills et al., 2011). For example, inhibition-of-return (IOR: slowed responding at previously fixated locations) is observed in search tasks whereas facilitation-of-return (FOR: speeded response at previously fixated location) is observed in non-search tasks. In the present series of four experiments, we examine the influence of task set and task switching on IOR/FOR and oculomotor kinematics (e.g., saccade amplitude, fixation duration). Participants view scenes while either searching for a target (embedded N or Z), memorizing the scene, or evaluating the scene, with task set being either blocked or mixed. Search type is also manipulated between experiments. Both task set and task switching lead to substantial behavioral changes in oculomotor kinematics, with the most surprising changes relating to IOR/FOR. Whereas IOR is observed during search when task set is blocked, replicating previous findings, when task set is mixed, IOR is only observed during search when the previous trial also required a search. If preceded by a different task set, FOR is observed during search. These experiments provide important insight into the costs and benefits associated with task switching as it relates to visual behavior, in addition to demonstrating the flexibility of the visual system.
Meeting abstract presented at VSS 2014