3 reasons why we need eye movement
we need eye movement because
- the spatial resolution drops with increasing eccentricity
- best spatial resolution at fovea
- processing colour mainly at fovea
how many saccades do we make per second/day?
per second: 3-4
per day: 230 000
if we make so much eye movements, why is the world still stable?
during the saccades we cannot see
what is the difference between overt and covert attention?
overt attention: attention with eye movement
covert attention: attention without eye movement
what did Yarbus find in 1967?
> eye movements are depending on top-down knowledge (in this case, task instructions)
> this reflects enogenous (goal-driven) attention
what is exogenous attention
> with respect to eye movement?
exogenous: stimulus driven attention
> responsible for involuntary eye movements
how does goal-driven and stimulus- driven attention act when searching for a target under distractors?
> large effects of saliency for fast eye movement
> no effect of saliency on slow eye movement
> goal driven and stimulus driven selection act independently in different time windows
what relationship did daniel kahneman find with respect to pupil size and task difficulty?
pupil size increases in proportion to the difficulty of the task being performed
3 key facts on pupil size reactivity
- pupils constrict even when you only imagine a bright stimulus
- pupils react when you prepare eye movement to bright/dark area
- pupil size is good predictor of awareness (binocular rivalry)