Modification of human gastric acid secretion with operant-conditioning procedures.

Four healthy women sat in a lab. A tube in their stomach measured acid. A screen showed them a line that moved when acid went up or down. If they hit a high acid target they got money. If they hit a low acid target they also got money. The team flipped the target every few days to see if the women could follow the switch.

Three of the four women tripled their acid when the game paid for high acid. When the rule flipped and paid for low acid, they dropped back to baseline. The fourth woman showed the same pattern but smaller. The acid level tracked the money, not the clock. Clear operant control of a gut function.

Annable et al. (1979) got rats to wash their paws more with food pellets. E et al. did the same trick in people, but the reinforcer was cash and the response was stomach juice. Same rule: pick a biological act, pay for it, and it grows.

Corfield-Sumner et al. (1977) saw rats drink buckets of water after food deliveries. They called it schedule-induced polydipsia. E et al. show the same schedule logic can turn acid on and off, proving the gut can be schedule-controlled just like water intake.

Madden et al. (2003) put cocaine self-injection under stimulus control. E et al. did it with gastric acid. Together they say operant procedures can tame drug-taking and digestion alike. The mechanism is general.

If you can reinforce stomach acid you can probably reinforce any measurable body signal. Biofeedback sessions for heart rate, skin temp, or gut pH become behavior plans, not magic. Pick a signal, give clear feedback, add a reinforcer, and shape the curve. Your client learns to control the very thing you used to think was automatic.