The Binding Problem after an eye movement

Spatial attention is thought to be the "glue" that binds features together (e.g., Treisman & Gelade, 1980, Psychology, 12[1], 97-136)-but attention is dynamic, constantly moving across multiple goals and locations. For example, when a person moves her eyes, visual inputs that are coded relative to the eyes (retinotopic) must be rapidly updated to maintain stable world-centered (spatiotopic) representations. Here, we examined how dynamic updating of spatial attention after a saccadic eye movement affects object-feature binding. Immediately after a saccade, participants were simultaneously presented with four colored and oriented bars (one at a precued spatiotopic target location) and instructed to reproduce both the color and orientation of the target item. Object-feature binding was assessed by applying probabilistic mixture models to the joint distribution of feature errors: feature reports for the target item could be correlated (and thus bound together) or independent. We found that compared with holding attention without an eye movement, attentional updating after an eye movement produced more independent errors, including illusory conjunctions, in which one feature of the item at the spatiotopic target location was misbound with the other feature of the item at the initial retinotopic location. These findings suggest that even when only one spatiotopic location is task relevant, spatial attention-and thus object-feature binding-is malleable across and after eye movements, heightening the challenge that eye movements pose for the binding problem and for visual stability.