Avoidance response rates during a pre-food stimulus in monkeys.

Scientists watched monkeys press a lever to avoid mild shocks.

A food pellet dropped into the cage every few minutes.

Sometimes the monkey had to pick the pellet up after it landed. Other times it had to grab the pellet before it dropped.

The team counted how fast the monkey pressed the lever under each setup.

Monkeys pressed faster when they picked the pellet up after it landed.

They pressed slower when they grabbed the pellet before it dropped.

The simple change in food timing pushed avoidance rates up or down.

Skrtic et al. (1982) later showed monkeys can learn to avoid food itself if the shape was linked to illness. That study extends Henton (1972) by proving food cues can steer avoidance in more ways than just timing.

Navarick et al. (1972) ran a similar monkey avoidance lab the same year. They changed lights instead of food rules and also saw big rate swings. The two papers line up: tiny stimulus tweaks swing avoidance.

Foltin (1997) found that limiting food access made baboons treat drug solution like food. The shared theme is that food rules set the value of other behavior — a idea first hinted at in Henton (1972).

Your client may work for food or avoid something unpleasant. This study warns that the way you deliver the edible — before or after the response — can speed or slow other behaviors. Try dropping the reinforcer after the target response if you want more avoidance, or deliver it before if you want less. Test one change per session and track the rate.