Twenty-two naı̈ve undergraduates participated in a psychophysical experiment designed
to elucidate the neural events that allow us to see subtle motion differences. Half of the …

Two experiments were conducted to determine the extent to which perceptual learning
transfers between orientation and direction discrimination. Naive observers were trained to …

This study was conducted to determine whether humans' judgments about the speed and
direction of moving stimuli was differentially affected by transcranial magnetic stimulation (TMS)…

The motion of an object can be described by a single velocity vector, or equivalently, by direction
and speed separately. Similarly, our ability to see subtle differences in the motion of two …

Thirty-six Brown University students participated in three experiments designed to address
perceptual learning. In each experiment, visual discrimination thresholds were tracked over …

It has been known since the time of Helmholtz that vertical differences between the two
retinal images can generate depth perception. Although many ecologically and geometrically …

Dynamic environments often contain features that vary simultaneously as well as features
that vary sequentially. In principle, the correspondingly distinct sensations of simultaneity and …

A considerable body of sensory research has addressed the rules governing simultaneity
judgments (SJs) and temporal order judgments (TOJs). In principle, neural events that register …

We examined interactions between and within the left and right visual hemifields using
elementary visual tasks. Each trial required identifying a letter at fixation and then either …

Motion repulsion involves interaction between two directions of motion. Since attention is
known to bias interactions among different stimuli, we investigated the effect of attentional tasks …