AN ASSESSMENT OF REVERSAL INDEX

The results of recent experiments on reversal learning by cats and rhesus monkeys were reviewed to test the value of the ''reversal index'' of Rjalakshmi and Jeeves (1965) as a measure of comparative learning capacity. Values of the reversal index did not vary systematically among groups differing in age, species, previous testing experience, task difficulty, infantile stimulation or environmental enrichment. Values of the reversal index for the same animals tested in 2 different apparatuses were uncor-related. Several independent analyses indicated that the value of the reversal index for an individual or for a group is significantly related to the number of errors made in initial discrimination learning; this artifact implies that the reversal index has little or no merit for the comparative study of learning.