Waiting for more: The performance of domestic dogs (Canis familiaris) on exchange tasks

Abstract

Five domestic dogs (Canis familiaris) weretested in a cooperative exchange task with an experimenter, as previously tested in non-human primates. In the first task, the dogs exchanged to maximise payoffs when presentedwith food items of differing quality. All consistently exchanged lower-value for higher-value rewards, as determined by their individual food preference, and exchanges corresponded significantly with the spontaneous preferences of three dogs. Next, all subjects demonstrated an ability to perform two and three exchanges in succession, to gain both qualitative and quantitatively increased rewards (group mean = 72 and 92% successful triple exchanges, respectively). Finally, the ability to delaygratification over increasing intervals was tested; the dogs kept one food item to exchange later for a larger item. Aspreviously reported in non-human primates, there was considerable individual variation in the tolerance of delays, between 10 s and 10 min for the largest rewards. For thosewho reached longer time lags ([40 s), the dogs gave up the chance to exchange earlier than expected by each subject's general waiting capacity; the dogs anticipated delay durationand made decisions according to the relative reward values offered. Compared to primates, dogs tolerated relatively long delays for smaller value rewards, suggesting that the socio-ecological history of domestic dogs facilitates their performance on decision-making and delay of gratification tasks.