The Influence of Task Demands and Object Feature Dimensions on Saccade Target Selection.

Poster Session A - Saturday, April 13, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Daniel MacDonald¹ (dmacdo22@uoguelph.ca), Mazyar Fallah¹, Heather Jordan¹; ¹University of Guelph

Previous work has shown that similarity between a target and distractor in a delayed match-to-sample (DMtS) task can influence the curvature of the saccade (Giuricich et al, 2023; Kehoe & Fallah, 2023; Kehoe, Lewis & Fallah, 2021). Unresolved competition between target and distractor items produces saccade trajectories which curve towards the distractor, while resolved competition produces inhibition of the same distractor resulting in curvature away. Varying target-distractor similarity produces object-based effects on saccade metrics during the discrimination phase of competition, but no non-spatial influence once competition has been resolved. However, past research used stimuli which was sparce in object feature dimensions. By increasing the complexity and relevance of non-spatial visual characteristics required to resolve target-distractor competition, we explored the influence of feature versus bound object representations on saccades. Modifying the DMtS task to incorporate Wisconsin Card Sorting Task requirements, participants generated saccades to a target stimulus which matched on one object feature dimension (colour, shape or numerosity) with the probe. Distractors items varied on non-relevant object dimensions with the target item. If distractor suppression is not object-based, varying the number of features that are shared between the target and distractor should have no influence on saccade trajectories. However, we find evidence of feature-based influences, suggesting that competition in the oculomotor system is driven by non-spatial object representations. This work has implications for understanding the priority maps underlying target selection in a motor system under dynamic task and visual feature conditions.

Topic Area: EXECUTIVE PROCESSES: Goal maintenance & switching