Preference after training with differential changeover delays.

The team used a single-case lab design with pigeons. The birds pecked two keys that gave food at different rates.

A changeover delay (COD) switched between the keys. The COD lasted 2, 4, or 8 seconds across conditions.

They asked: does the length of the COD shape which key the bird prefers?

COD length made no clear difference. Birds still chose the key that paid off more often.

Only the rate of reinforcement steered choice. The delay schedule was noise.

Lattal (1974) mapped the same power-law rule in multiple schedules. Response rate rose with richer pay, just like here.

Ward et al. (2021) showed that an early, broad mand ("My way, please") does not block later, specific mands. Carmichael et al. (1999) echo this: early COD patterns do not lock in later choice.

Hranchuk et al. (2019) found that a brief modeling history doubles learning speed. Both papers show that history matters, but the payoff rate still rules.

When you set up concurrent schedules, skip long changeover delays if the goal is clear preference. Focus on making the richer schedule obvious. If a client vacillates between tasks, raise the rate of reinforcement for the target task instead of adding a wait rule. The science says the payoff, not the delay, drives the choice.