Inter-species comparisons of variation in magnitude of inhibitory control in reversal learning.

Abstract

Comparison of successive discrimination reversal (SDR) performances of a number of avian and mammalian species has increasingly suggested that SDR methodology yields inter-species differences of taxonomic and phyler~c Import. Perhaps the most promising hypothesis advanced to account for such differences has been thar of Krushinskii (1962) who suggests that such differences will arise because phyletically disparate species will differ in their capacity to inhibit previously correct, reinforceable responses, and not in their capacity to learn new, reinforceable responses. An initial test of this hypothesis can be provided by SDR dara already obtained in our laboratory, by comparing initial error data across successive reversal problems for phylerically disparate species. Initial error measures, defined as the number of incorrect responses following a reversal prior to the first correct response, are abbreviated measures of resistance to extinction. Thus, they can be viewed as reflecting the development of inhibitory control. Data from 3 species of Galliformes, pigeons, and Himalayan Magpies, representing respectively lower and higher avian species, as well as data from Squirrel and Capuchin monkeys were analyzed. All dara were obtained from a spatial SDR task, previously described (Gosserte & Cohen, 1966; Gossette & Inman, 1966). Table 1 presents mean initial error data across 20 problems for the 7 species. Analysis by Kcuskal-Wallis test showed that the primate performance was superior ( p < ,001) to