Perceptual fluctuations of illusions as a possible physical fatigue index.

Abstract

The problem was to determine whether or not physical fatigue could be measured by means of fluctuations of perceptual illusions which could be observed in 2 or 3 different ways. Fatigue was produced by the following methods: foot-ball practice, basket-ball practice, fatigue exercise and rugby. Results show that physical fatigue tends to produce for most individuals more fluctuations. A figure which can be observed in 3 ways appears to fluctuate more than the one which can be observed in 2 different ways. Different illusions shown to the same group do not appear to fluctuate at the same rate. It is also possible that the type of fatigue situation may be responsible for the difference in the number of fluctuations. In no fatigue situation or for no one illusion is there 75% agreement among the subjects. Consequently, these differences would not be adequate as fatigue indexes for individual prediction.