DISCRIMINATIVE VOCAL CONDITIONING IN RHESUS-MONKEYS - EVIDENCE FOR VOLITIONAL CONTROL

Both emotional and volitional systems are invoked in explaining the control of human vocalizations, but vocal behavior of nonhuman primates is often believed to be totally under emotional control. Monkeys' poor performance on conditioning tasks, especially discriminative conditioning of vocalization (DCV), has been cited as evidence against volitional control. In Experiment 1, rhesus monkeys failed a DCV task in which food was given for vocalizations emitted during an arbitrary visual stimulus, but in Experiment 2, monkeys showed clear discriminative performance when an otherwise comparable shock-avoidance DCV procedure was used. This evidence that monkeys possess some degree of volitional control has implications for the relation between animal vocalizations and the origin of human speech. © 1979.