Performance of Normal and Brain-Operated Monkeys on Mechanical Puzzles with and without Food Incentive

Abstract

A. INTRODUCTION AND PROBLEMIn previous studies Harlow, Harlow, and Meyer (4) and Harlow (3) have shown that monkeys learn to solve mechanical puzzles and maintain this performance for many trials without food or any other extrinsic incentive. A manipulation drive was proposed to account for both the learning and the persistence of the behavior. In the present investigation mechanical puzzle performance is measured over a longer period of time than in previous investigations. Brain-operated as well as normal monkeys are used as subjects, and the effect of an interposed food-incentive condition is analyzed. B. SUBJECTSAll had extensive testing experience and, with the exception of the occipital group, identical laboratory histories. Four were normal, four had undergone extirpation of one occipital Jobe, four had been subjected to extensive unilateral decortication (subsequently designated as the EUD Group), and four had undergone extensive unilateral decortication plus removal of the lateral surface of the remaining frontal lobe (subsequently designated as the EUDALF Group).Extensive unilateral decortication involved sparing only of Areas 4 and 6, and 3, 1, 2.2 C. APPARATUST h e essential apparatus was the mechanical puzzle illustrated in Figure 1. It consisted of a board on which were mounted the six devices: a vertical pin, a horizontal pin, a door-stop, a bolt, a hasp, and a hinge. These devices were so arranged that they could be opened only in serial order and, once released, did not automatically close. Actually, closing of the devices by Sixteen macaque monkeys served as subjects. *Received in the Editorial Office on October 18, 1949. 'Supported in part by th,e Research Committee of the Graduate School from funds 9All of the operated monkeys were chronic preparations and had been allowed a supplied by the Wisconsin Alumni Research Foundation. minimum of 90 days postoperative recovery. 305

Intrinsic Motivation and Self-Determination in Human Behavior

“…Harlow and his associates (Davis, Settlage, & Harlow, 1950;Gately, 1950;Harlow, 1950Harlow, , 1953aHarlow et al, 1950) showed repeatedly that manipulating a complex mechanical puzzle made up of hasps, hooks, and hinges was intrinsically rewarding for monkeys and could be used to strengthen other responses. He posited a manipulation drive to account for these findings.…”

“…In those studies, monkeys manipulated a mechanical puzzle apparatus, and food was introduced into the situation for some of the monkeys. In one study, Davis et al (1950) found that performance was better after this reward had been introduced and terminated than it had been before the reward was introduced. This suggests that the experience with food led the monkeys to imbue the activity with greater intrinsic value, so they were more interested in performing it well.…”

The Psychology and Neuroscience of Curiosity

“…Specific curiosity referred to desire for a particular piece of information, while diversive curiosity referred to a general desire for perceptual or cognitive stimulation (e.g., in the case of boredom). For example, monkeys robustly exhibit specific curiosity when solving mechanical puzzles, even without food or any other extrinsic incentive (e.g., Davis, Settlage, & Harlow, 1950; Harlow, Harlow, & Meyer, 1950; Harlow, 1950). However, rats exhibit diversive curiosity when, devoid of any explicit task, they robustly prefer to explore unfamiliar sections of a maze (e.g., Dember, 1956; Hughes, 1968; Kivy, Earl, & Walker, 1956).…”

The competing response hypothesis of decreased play effects: A reply to Lepper and Greene.

“…If decreased play effects, however, are stimulus novelty effects, repeated trials of training should weaken such effects. The available evidence consistently suggests that decreased play effects are not associated with multipletrial, contingent reinforcement procedures (e.g., Davis, Settlage, & Harlow, 1950;Feingold & Mahoney, 1975;Reiss & Sushinsky, 1975b).…”