The Pulfrich Effect: Alpern (1968)

Note: Permission to reproduce this paper has been withheld by the publisher,
The American Psychological Association.

Abstract

A theoretical treatment of the Pulfrich effect is developed for combining data on the assumption that the time constant at corresponding depths in any human visual system will be the same for both eyes.

A superthreshold model of latency based on the Hodgkin-Huxley equations is derived. Setting a solution of the homogeneous system equal to the input retinal illuminance I yields a time constant tau such that,

for v_n the output of the n-th serial stage of visual processing, tau₀ a dark-current time constant, and w a scaling constant.

This approach leads to a power-function formula for the Pulfrich latency,

in which K is an arbitrary scaling constant, and T₀ represents an offset latency associated with the lower-I Pulfrich target.
Lit's classic 1949 data then are fit almost perfectly by this formula with n = 4, K = 78, and T₀ = 71.9.

One conclusion is that the system yielding the Pulfrich latencies must be equivalent temporally to a system with about four Hodgkin-Huxley-like stages.

Email Comments.

Back to Pulfrich Effect Home. University Privacy Policy