Two unlike patterns of random-ratio responding associated with different eating habits in rhesus monkeys.

Four rhesus monkeys pressed a lever for food pellets. The schedule was a random-ratio: every press had a set chance of payoff, like a slot machine.

The scientist watched how each monkey ate. Two animals bolted pellets fast. Two held each pellet and nibbled.

Sessions ran until the monkeys stopped responding. The goal was to see if eating style matched lever-pressing style under the same ratio odds.

Fast eaters pressed fast. They rarely paused after food and their rate climbed when the payoff odds worsened.

Slow eaters pressed slow. They took long breaks after each pellet and kept a steady, low rate no matter the odds.

A simple habit—how a monkey handles food—predicted the whole response pattern on the lever.

Russell et al. (2018) later showed children with autism working for tokens on a progressive ratio. Tokens kept kids going longer than food alone, extending the monkey finding that reinforcer type (or style) alters ratio performance.

Michael (1974), from the same lab and year, proved that schedule context can flip what a signal is worth. Together the papers warn: schedule effects depend on both the animal’s habits and the surrounding cues.

Rogers-Warren et al. (1976) found that pigeons pecking for food on interval schedules suddenly attacked a picture of another bird. Like the monkeys’ eating quirks, this collateral behavior was tied to the food schedule, showing schedule-induced habits across species.

When a client’s response pattern looks odd, check their “eating style” equivalents—how they hold a pencil, wait for tokens, or handle edibles. These collateral habits can override the schedule you programmed. Try letting the child eat a reinforcer in their natural way before you label the session a failure; the schedule may be fine, the habit is the signal.