Delayed gratification: A grey parrot (Psittacus erithacus) will wait for more tokens.

Delay of gratification, the ability to forgo an immediate reward and wait to gain a reward better in either quality or quantity, has been used as a metric for temporal discounting, self-control, and the ability to plan for the future in both humans (particularly children) and nonhumans. Several avian species have been able to wait for a better quality reward for up to 15 min, but none seem able to wait for a better quantity reward for any significant period of time. Using a token system (where each wooden heart represents 1 nut piece), we demonstrated that a Grey parrot-who had previously waited up to 15 min for better quality-would now wait for better quantity, again for up to 15 min. Thus, symbolic distancing-that is, removal of the immediate presence of the hedonic item-enabled him to perform at levels comparable with young children on the classic test and might be a viable method for training executive function. (PsycInfo Database Record (c) 2022 APA, all rights reserved).