Avoidance behavior and the development of gastroduodenal ulcers.

BRADY et al. (1958) watched 15 rhesus monkeys for months. The monkeys pressed levers to avoid electric shocks. Some also pressed to give themselves brain shocks.

The sessions ran up to 24 hours a day. The team wanted to see if long avoidance training hurt the animals.

Every monkey got deep stomach or gut ulcers. Some bled and died. The longer the avoidance schedule, the worse the damage.

Even monkeys that only pressed for brain shocks got ulcers. Chronic stress from the task, not just shock, seemed to cause the harm.

Belacchi et al. (2014) gives hope. One 15-minute acceptance-defusion exercise wiped out lab-made avoidance in humans. It shows we can remove avoidance without hurting the body.

Hake et al. (1967) and Thomas et al. (1968) used the same monkey-shock setup. They mapped how shock strength changes behavior and biting attack. None checked inside the body. BRADY et al. (1958) fills that gap by showing the hidden damage.

Morse et al. (1966) found that stopping food made pigeons attack each other. Together these papers warn: aversive procedures, whether shock or loss, can spark side effects you do not see right away.

If you run or supervise avoidance protocols, think past the response rate. Schedule breaks, check salivation, appetite, or weight. Use brief defusion drills like Belacchi et al. (2014) instead of endless avoidance chains. Your learners’ stomachs may thank you.