Relative and absolute strength of response as a function of frequency of reinforcement.

HERRNSTEIN (1961) worked with pigeons in a lab. The birds could peck two keys. Each key had its own schedule. The schedules set how many pecks paid off.

The team changed the minimum pecks needed for food. They watched how the birds split their pecks between the two keys.

The pigeons matched their pecking to the payoff odds. If the left key paid after 10 pecks and the right after 30, birds pecked the left key three times more.

Response strength tracked reinforcement frequency almost perfectly.

Mandell (1984) conceptually replicated the finding. Pigeons still tracked payoff rate, but the 1984 birds used that rate as a signal to tell schedules apart. Same core idea, new angle.

Aman et al. (1987) extended the work. They showed that even a brief light before a schedule change gained control, even though pecking that light never paid. The 1961 frequency rule still held, but time cues also mattered.

Elsmore et al. (1994) extended the idea to rats in an eight-arm maze. Nose-poke rates followed payoff odds, just like pigeon key pecks. The matching law crosses species and tasks.

Your client’s behavior will shift toward the richer schedule. If you run two programs, put the stronger reinforcer on the target you need most. Watch for accidental matching to the wrong schedule—kids may pick the easy task if it pays better. Rebalance payoffs and you rebalance behavior in the next session.