One longstanding question is how early in the visual system attention exerts its influence.
Here we show that an effect of attention can be measured at the earliest possible stage of …

The eye's pupils constrict (shrink) in brightness and dilate (expand) in darkness. The
pupillary light response was historically considered a low-level reflex without any cognitive …

We measured pupil size in adult human subjects while we manipulated both the luminance
of the visual scene and the location of attention. We found that, with central fixation …

Here we show that the pupillary light response reflects exogenous (involuntary) shifts of
attention and inhibition of return. Participants fixated in the center of a display that was …

Does attention alter appearance? This critical issue, debated for over a century, remains
unsettled. From psychophysical evidence that covert attention affects early vision—it …

The pupillary light response has long been considered an elementary reflex. However,
evidence now shows that it integrates information from such complex phenomena as …

We recorded by use of an infrared eye-tracker the pupil diameters of participants while they
observed visual illusions of lightness or brightness. Four original illusions {based on …

The pupillary light response is an important automatic physiological response which
optimizes light reaching the retina. Recent work has shown that the pupil also adjusts in …

The pupil constricts in response to light increments and dilates with light decrements. Here
we show that a picture of the sun, introducing a small overall decrease in light level across …

This review focuses on covert attention and how it alters early vision. I explain why attention
is considered a selective process, the constructs of covert attention, spatial endogenous and …