Effects of morphine, clonidine, and intensity change on electric-shock discrimination.

Scientists gave squirrel monkeys a simple shock test. The monkeys had to tell a weak shock from a strong one. If they picked right, they avoided extra shock.

The team then injected the monkeys with morphine or clonidine. They wanted to see if the drugs changed how well the monkeys could feel the difference.

Both drugs made the monkeys worse at the job. They picked the wrong shock level more often. They also took longer to press the button.

Higher drug doses made the drop in accuracy even bigger.

Lie et al. (2010) ran a similar shock test with people. They found that changing how often shocks happen changes where people place their bets, but it does not change how well they actually feel the shocks. Spangler et al. (1984) shows that drugs, not shock odds, can directly dull the sense of intensity.

Rider et al. (1984) showed that pigeons also lose accuracy when they have to wait before choosing. Both delay and drugs hurt stimulus control, just through different paths.

Aman et al. (2002) paired new lights with shock and later found those lights could control new behavior. Their work shows shock can build stimulus classes, while F et al. shows drugs can tear that control down.

If your client takes morphine or clonidine, do not assume poor discrimination means the teaching plan is bad. The drug itself can blur stimulus control. Track timing of doses and error patterns. You may need to lower task difficulty or wait until the medication peak passes before running critical probes.