Copy rats: Learning by observation during a foraging task by rats.

In two experiments, rats observed expert foragers in a laboratory foraging task. In both experiments, 12 towers with a food cup on top of each tower were placed in a circle. Six towers, marked with black and white stripes, had cups baited with cheese, and were located in randomly selected positions on successive trials. The other six towers were white with food cups that were sham baited with inaccessible food. In both experiments, during Phase 1, demonstrator rats eventually learned to find the baited towers, making approximately 90% correct choices in their first six choices. In Phase 2, observer rats each had an opportunity to observe, from a cage located inside the circle of towers, a now-expert demonstrator forage. Half of the observers were able to observe a cage mate, whereas the other half of the observers were able to observe a non-cage mate. After a delay of about 2 min (Experiment 1) or about 24 h (Experiment 2), the observers were allowed to forage among the rebaited towers. In both experiments, the observers performed better during their 20 Phase 2 trials than the demonstrators had performed during their first 20 Phase 1 trials. But, in both experiments, there was no clearly significant difference between the performance of observers able to watch cage mates as opposed to non-cage mates. Because the observational effect seen in both experiments survived a 24-h delay between observation and performance, it was deemed to have been based on learning.