Velocity discrimination thresholds for flowfield motions with moving observers

Velocity discrimination thresholds for flowfield motions with moving observers

The visual flow field, produced by forward locomotion, contains useful information about many aspects of visually guided behavior. But locomotion itself also contributes to possible distortions by adding head bobbing motions. Here we examine whether vertical head bobbing affects velocity discrimination thresholds and how the system may compensate for the distortions. Vertical head and eye movem...

Discrimination by Parallel Observers

Infant direction discrimination thresholds

Although adults can detect direction differences as small as 1 arc degree, the ability of infants to discriminate direction of motion is less clear. This study measures the precision with which 6-, 12-, and 18-week-old infants discriminate direction of motion. Infants viewed random dot kinematograms in which a direction difference between the target and background dots defined a circular target...

Measuring visual form discrimination with blur thresholds.

A method is described for gauging the discriminability of spatial forms. Rather than challenging form discrimination by size reduction as is done in testing visual acuity, the maximum image degradation by blurring is determined that still allows shape recognition. The procedure has the advantage that tests are substantially independent of optical (resolution) and retinal (light-processing) stag...

Visual discrimination thresholds for time to arrival.

In a seminal article, Todd (Journal of Experimental Psychology: Human Perception and Performance 7:795-810, 1981) reported a difference threshold of about 50 ms to discriminate the times of arrival of two differently sized objects that simultaneously approached head-on at constant but different velocities. Subsequent investigators, however, have often found much higher thresholds. We did one co...