Air-blast avoidance learning sets in protein-malnourished monkeys

Abstract

The present experiment was designed to minimize known motivational differences among malnourished and non-malnourished organisms, and incorporated a task found useful in the identification of differences in learning capacity. Rhesus monkeys, maintained on either a 3.5% casein (low protein) diet or a 25% casein (high protein diet control) diet by weight were trained to a stringent criterion under an object-quality avoidance discrimination learning set procedure with pressurized air as the negative reinforcer. Across several dependent measures of learning, the performance of both groups was consistently similar, and indicated that the low protein animals were capable of learning individual discrimination problems within a few trials. The failure to observe any apparent differences between experimental and control subjects on such factors as adaptation to the testing procedure, responsiveness to the aversive stimulus, and the frequency of stimulus perseveration errors, suggests that minimizing the motivational and emotional differences between normal and malnourished monkeys was responsible for the lack of differences in learning behavior.