Abstract
Like humans, monkeys make saccades nearly three times a second. To understand the factors guiding this frequent decision, computational models of vision attempt to predict fixation locations using bottom-up visual features and top-down goals. How do the relative influences of these factors evolve over multiple time scales? Here we analyzed visual features at fixations using a retinal transform that provides realistic visual acuity by suitably degrading visual information in the periphery. In a task in which monkeys searched for a Gabor target in natural scenes, we characterized the relative importance of bottom-up and task-relevant influences by decoding fixated from nonfixated image patches based on visual features. At fast time scales, we found that search strategies can vary over the course of a single trial, with locations of higher saliency, target-similarity, edge- energy, and orientedness looked at later on in the trial. At slow time scales, we found that search strategies can be refined over several weeks of practice, and the influence of target orientation was significant only in the latter of two search tasks. Critically, these results were not observed without applying the retinal transform. Our results suggest that saccade-guidance strategies become apparent only when models take into account degraded visual representation in the periphery.
Original language | English (US) |
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Article number | 19 |
Journal | Journal of Vision |
Volume | 15 |
Issue number | 3 |
DOIs | |
State | Published - 2015 |
Funding
This work was funded by NIH Grant 1R01EY021579-01A1. We thank B. M. ‘t Hart for useful discussions and comments on the manuscript.
Keywords
- Edge-energy
- Eye movements
- Natural scenes
- Nonhuman primates
- Orientation statistics
- Peripheral vision
- Priority map
- Relevance
- Saliency
- Visual search
ASJC Scopus subject areas
- Ophthalmology
- Sensory Systems