Performance On Concurrent Variable-interval Extinction Schedules.

The team placed six pigeons in operant chambers. Each bird faced two keys. One key paid off on a variable-interval schedule. The other key never paid off — an extinction schedule.

Sessions ran daily over the study period. Researchers recorded every peck. They wanted to see if the birds would learn to peck only the paying key.

The birds kept pecking both keys. They did not switch to the paying key. Response rates stayed mixed even after long training.

The result fits contingency-discriminability theory. When the difference between payoff and no-payoff is hard to feel, animals stick with old habits.

Winett et al. (1991) saw a different outcome. Adults with heat-lamp reinforcement shifted toward the richer option. Humans noticed the payoff gap faster than pigeons.

Eisler (1984) also used pigeons on concurrent VI schedules. Adding limited-hold windows changed choice. That study backed melioration, not matching. Both papers show that small procedural tweaks swing the theory.

Kydd et al. (1982) found the same null pattern when they tested immediacy. Pigeons ignored small timing differences. The 1998 study extends this idea: birds also ignore small rate differences when one option is zero.

If your client splits time between two tasks and one task never pays off, do not expect quick exclusivity. Build bigger contrasts. Make the payoff obvious with richer magnitudes, clearer signals, or brief extinction probes. Teach the learner to feel the difference, not just to hear it.