Starlings and the ephemeral reward task: why timing makes or breaks success

What is it about?

We studied spotless starlings using the “ephemeral reward task”, where one choice gives a single piece of food and ends the trial, while another choice gives the same food and then a second piece shortly afterwards. We show that starlings can learn to choose the option that brings them more food overall, and can adjust when we change which option is best. This contrasts with many previous studies in pigeons and other animals, which reported failures in this task. By gradually making the wait between the first and second rewards longer, we found that starlings also start to fail under less favourable timing conditions. This suggests that differences between species may reflect how they cope with timing and memory demands, rather than simple “smart” vs “not smart” labels.

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Photo by Seth Wickham on Unsplash

Photo by Seth Wickham on Unsplash

Why is it important?

This work helps us rethink what it means when animals “fail” a cognitive task. The ephemeral reward task has often been used to argue that some species have special decision-making abilities and others do not. Our study shows that spotless starlings can succeed at this task, but only under certain timing conditions. When we stretch the delay between rewards, they start to look just like species that were previously labelled as poor performers. This suggests that small changes in timing and memory demands can strongly shape how “clever” animals appear. Understanding this matters for how we design fair tests of animal cognition, and how we interpret animals’ choices in real-world situations where rewards are delayed or uncertain.

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