Effects of primary reinforcement on pigeons' initial-link responding under a concurrent chains schedule with nondifferntial terminal links.

Ploog (2001) worked with pigeons in a two-key cage. Each key started a chain that ended with the same color light and the same delay.

The only difference was the amount of grain that followed. One side gave three pellets, the other gave one. The birds could hop back and forth before they chose.

In 57 out of 60 tests the pigeons pecked first on the side that led to the bigger snack. They kept doing this even though the terminal lights told them nothing about what was coming.

The result shows that primary reinforcement size alone can steer choice. No special signals or extra information are needed.

Malone (1975) had earlier shown that pigeons like choice and informative lights. Ploog (2001) removed the information and still got clear preference, proving the grain amount is enough.

Millard (1979) found that local timing between reinforcers, not their total number, guided choice. Ploog (2001) agrees that amount matters, but shows the pure size effect when timing is held equal.

Gureghian et al. (2020) later moved the idea to children with autism. They let kids pick a reinforcer after the response, not before, and skills grew faster. The shared theme: when the reinforcer is delivered can be as powerful as what is delivered.

You can trust the size of the payoff to drive behavior even when the cues are boring or the same. In practice, give a bigger or better reinforcer instead of adding flashy lights or extra words. If you want quicker acquisition, save the choice moment for right after the response, just like the birds taught us.