Operant conditioning of autogrooming in vervet monkeys: Cercopithecus aethiops.
Food rewards can dial grooming up or down and lock in specific styles, showing that even natural behaviors are open to operant control.
01Research in Context
What this study did
Researchers worked with vervet monkeys in a lab.
They used banana pellets to make grooming happen more or less.
The team also shaped different grooming styles, like focusing on the tail or chest.
What they found
Food rewards reliably raised or lowered how much the monkeys groomed.
The monkeys also learned to favor the exact grooming form that earned pellets.
Even a natural behavior can be turned up or down with simple reinforcement.
How this fits with other research
Leander et al. (1972) showed monkey sounds can be put on a schedule too.
Sachs et al. (1969) found that steady reward tightens response form, matching the grooming result.
Quilitch et al. (1973) saw the opposite: pigeons got stuck in rigid patterns even when the study paid for variety.
The monkey study proves reinforcement can sculpt form, while the pigeon study warns that rigidity can still sneak in.
Why it matters
You can shape self-care or stereotypy in clients by controlling what follows the act.
Pick the exact form you want—hand-washing style, toy play, or greeting—and reinforce only that form.
Watch for rigid loops; if they appear, add variety requirements or change the schedule.
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02At a glance
03Original abstract
Vervet monkeys received food reinforcement contingent on autogrooming. Experiment 1 reinforced grooming on a schedule of increasing intermittency and grooming increased in frequency and duration; with only pauses reinforced, grooming decreased in frequency and duration. Experiment 2 demonstrated differentiation of operant autogrooming; in each session a different single form of grooming was reinforced (for example, grooming the tail only), and that form increased in frequency while other forms became less frequent. In Experiment 3 scratching was succesfully conditioned with a method that selectively reinforced variety in behavior; reinforcement was contingent on a shift in scratching form. In Experiment 4, with no contingencies on grooming, a prefood stimulus did not increase autogrooming whether or not grooming had previously resulted in contingent reinforcement. The form of conditioned autogrooming resembled the form of unconditioned autogrooming. The discussion suggests how reinforcement principles can account for changes in the topography of operant behavior.
Journal of the experimental analysis of behavior, 1984 · doi:10.1901/jeab.1984.42-171