Crows make optimal choices based on relative probabilities.

A recent study by Johnston, Brecht, and Nieder (2023, Current Biology, 33, 3238-3243) finds that carrion crows associate varying rates of reinforcement with novel arbitrary stimuli and make optimal decisions when they must later choose between stimulus pairs. These results demonstrate that crows are capable of not only storing information about reward probabilities in their memory but also making optimal choices based on this information even a month later.