Stuart Anstis

Stuart M. Anstis is a professor emeritus of psychology at the University of California, San Diego, in the United States.

[2] In 2013, Anstis won the Kurt Koffka Medal for "advancing the field of perception ... to an extraordinary extent".

[3] This chart[4] demonstrates how acuity falls off progressively owing to the increasingly coarser grain of the peripheral retina.

IN practice the luminance of the adapting light can follow a repetitive 1 Hz rising or falling sawtooth.

The afterimage is greatly strengthened if the white test field includes a black outline of the adaptor.

In the top row, a grey cross looks apparently darker on a light than on a dark surround.

If you jog on a slowly rotating turntables and then try to run in place, you will end up facing in a different direction.

This implies adaptation of low-level neural motion detector with no top-down cognitive input.

A dark-blue and light yellow square both move smoothly to the right in step on a grey surround.

When the dark square lies on a white stripe it is high in contrast and appears to move rapidly.

The thin gray spokes never change their brightness or position, yet they appear to drift around counterclockwise.

At low magnifications (or when viewed from farther away) all the jumps are visible and the patterns appears to drift down to the right towards 4 o'clock.

Conclusion: perceptual correlation between successive movie frames fails for oversized jumps.

In this case the CW motions of the tips (terminators) of the lines propagate to the center and are blindly assigned to the rotating intersection.

But fixate in the middle and the very same movements can spontaneously re-group into a more global view, of two pulsating, intersecting octagons.

When viewed in the periphery, the spot appears to move obliuely down to the left, parallel to the background stripes.

In peripheral vision, crowding makes it impossible to resolve the orientations of the zigzag strips in the surround.

Squares that are flashed at the reversal points of these patterns distortions show massive changes in size and shape.

This motion-induced position shift resembles the well-known flash-drag effect but is about 10 times larger.