Visual attention and stability

Abstract

In the present review, we address the relationship between attention and visual stability. Even though with each eye, head and body movement the retinal image changes dramatically, we perceive the world as stable and are able to perform visually guided actions. However, visual stability is not as complete as introspection would lead us to believe. We attend to only a few items at a time and stability is maintained only for those items. There appear to be two distinct mechanisms underlying visual stability. The first is a passive mechanism: the visual system assumes the world to be stable, unless there is a clear discrepancy between the pre-and post-saccadic image of the region surrounding the saccade target. This is related to the pre-saccadic shift of attention, which allows for an accurate preview of the saccade target. The second is an active mechanism: information about attended objects is remapped within retinotopic maps to compensate for eye movements. The locus of attention itself, which is also characterized by localized retinotopic activity, is remapped as well. We conclude that visual attention is crucial in our perception of a stable world.

Visual stability

“…We varied the time of target presentation with respect to the saccade in order to test whether predictive remapping might influence the processing of the target stimulus. We found that the discrimination of the target stimulus increased dramatically when it was presented shortly before a saccade [59]. In other words, the intention to make a saccadic eye movement 'unmasked' the target, even when both target and mask were shown in the same retinal position.…”

“…In addition, a number of interesting effects have been reported which are neither spatiotopic nor retinotopic in nature [8,58,59]. For example, we recently tested shape discrimination for a brief target that was followed by a mask.…”

Spatiotopic coding and remapping in humans

“…There is much evidence that only attended objects are remapped (e.g. [43]), and several other chapters in this issue highlight the importance of attention in visual stability and remapping, particularly Wurtz et al [44] and Mathô t & Theeuwes [45].…”

“…For example, Mathô t & Theeuwes [45] believe that the 'anticipatory RF shift allows neurons to take a 'sneak peak' at the location which will be brought into the RF'. Similarly, Wurtz et al [44] suggest that 'comparing the activity in the RF after the saccade to the activity in the future RF before the saccade is a potential mechanism that might underlie the perception of visual stability'.…”

Feature-based attention across saccades and immediate postsaccadic selection

“…We investigated whether feature-based attention plays a role in landmark search. In this framework, attention selects the saccade target that serves as a landmark pattern (Mathôt & Theeuwes, 2011) and is involved in the search for that target once the eyes land.…”