Waiting for reward: preference for signalled delays increases with average wait time

When rewards occur after a delay, signals that the wait will be shorter than average can be valuable. A recent study by Macias et al. (2024) found that pigeons preferred an alternative providing signals for a short or long delay to food over an alternative that provided no signals about delay. Preference for the signalled alternative increased with increases in the ratio of the long to short delay, with the average delay held constant. Here we report a preregistered experiment that tested the effect of changing the average delay, with the ratio of long to short delays held constant. Pigeons preferred the signalled alternative, and this preference was higher at longer delays (20 s and 40 s) than shorter delays (2 s and 4 s). This finding is opposite to the predictions from the modified Delta-Sigma model proposed by Macias et al., but fits well with predictions of the Signal for Good News (SiGN) model, which assumes that signals for a reduction in delay to reward reinforce choice.