Scientists have said for years that sleeping and dreaming play a role in categorizing memories. Sleep Review published an article this week about a study at the University of Chicago that seems to prove that point, at least among starlings…
“We really wanted to behaviorally show that these types of sleep-dependent memory benefits are occurring in animals,” said lead author Timothy Brawn, graduate student at the University of Chicago. “What was remarkable was that the pattern here looks very similar to what we see in humans. There wasn’t anything that was terribly different.”
To conduct the study, Brawn and colleagues trained starlings to discriminate between two 5-second snippets of birdsong in a learning task called a go-nogo procedure. If the starlings heard one song, the “go” stimulus, they would receive a food pellet after correctly poking their beak into a hole in their cage. If the other song, the “no-go” stimulus, was played, it signaled that the bird should not poke its beak in the hole, or else the lights in the cage were briefly shut off.
Groups of starlings were trained in the task at different times of day, then retested later to see how well they retained their learning. In all groups, performance on the task improved after the birds slept, relative to their performance before sleep. This result replicated the sleep-dependent enhancement pattern observed in human studies.