On loss aversion in capuchin monkeys.

Alan and coworkers gave capuchin monkeys two options. One choice delivered food right away. The other choice added a short wait before the same food.

The team watched which option the monkeys picked. They wanted to see if the monkeys acted like humans who hate losing things.

Monkeys avoided the option with the extra wait. The delay, not fear of loss, pushed their choice.

When both choices paid off at once, the bias vanished. Timing of food, not feelings about loss, ruled the results.

Barrett et al. (1987) ran a similar lab test. They inserted a three-second gap inside a chain of tasks. Response rates dropped 60-a large share in the link that now had the gap. Both studies show delay, not mind tricks, cuts behavior.

Carmichael et al. (1999) worked with human subjects. They let people pick their reward either early or right before delivery. Within-session choice lifted responding more than early choice. Again, quicker access drove the effect.

Terrace (1969) first showed monkeys learn fast under simple reinforcement. Alan’s 2008 study keeps the same species and lab style, but swaps avoidance training for a choice task. The theme stays the same: reinforcement timing steers behavior.

If a client stalls or avoids, check when the reinforcer arrives. A tiny delay can look like refusal or loss aversion. Tighten the schedule first; you may fix the problem without adding new procedures.