Saccade trajectory deviations in Van der Stigchel and Theeuwes (2007): General inhibition, or inhibition-of-return

Van der Stigchel and Theeuwes (2007) examined oculomotor system activation in a series of standard Posner-style endogenous cuing experiments. On a small subset of trials, rather than discriminate a target at a cued or uncued location, participants were instructed to execute a saccadic eye movement from the center fixation point to a saccade target near the top of the display. Results showed that trajectories of these saccades deviated away from the cued location, suggesting oculomotor activation in what was presumably a purely covert shift of visual spatial attention. An account based on saccadic inhibition for cued locations was offered. The current work sought to replicate these results and explore the nature of the proposed inhibition by adding more rigid control over time delay conditions between cue and target presentation. Results across both experiments showed the classic Posner cuing effect and no significant trajectory deviations due to the time delay conditions, but a strong right-directed bias in saccade deviations was observed regardless of cue direction. Potential explanations for this novel finding are discussed.