Voluntary switching in an invertebrate: The effect of cue and reward change

When faced with multiple competing goals, individuals must decide which goal to attend to. Voluntary task switching is an important paradigm for testing cognitive flexibility and spontaneous decision-making when competing tasks are present. Of particular importance is the study of how reward affects task switching, as reward is perhaps the most commonly used tool for shaping both human and animal behavior. Recently, Fröber and Dreisbach (2016) demonstrated that it is not reward level per se, but reward change, which most strongly affects switching behavior in humans: Task switching was lowest when reward remained high and highest when reward is changed (increase or decrease), while the repetition of low reward showed intermediate switching levels. Here we replicate their experiment on individual foragers of the ant species Lasius niger. Using an adapted spontaneous alternation task, we find that ants' switching response in light of their immediate reward history is qualitatively identical to that of humans. In a second experiment, we show that some of this behavior can be explained by the cue change, rather than the rewards. However, patterns exist in the data which cue change cannot explain. The striking parallel in behavior between humans and insects raises questions about how reward shapes behavioral flexibility and stability in humans. (PsycINFO Database Record