WORKING MEMORY OF <i>MACACA MULATTA</i> MONKEYS FOR COLOR AND MONOCHROME IMAGES

Abstract

In behavioral experiments, we studied the ability of rhesus monkeys (Macaca mulatta) to keep in working memory visual objects that differ either in shape, or in color, or in a combination of these features. Six male rhesus monkeys performed a delayed matching-to-sample task, with three geometric shapes from a set of stimuli as samples. In the first series of experiments, these were colored figures of various shapes, in the second – circles of different colors, in the third – monochrome images of various figures from the set of stimuli. When using both features to memorize objects, the monkeys showed the maximum result, and the task of matching by color performed better than the task of matching by shape. The latter result disagrees with the data (Fehring et al., 2022), where in similar experiments, though with one sample, the opposite bias was observed. The reason for this may be the shift from local features (contours of shapes) to global ones (color) when recognizing and memorizing visual objects under conditions of a greater memory load in our study.