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Wednesday, June 17, 2009

Fishes 'have human ability to learn'


Fishes are more clever than you thought, for a new study has found that although worlds apart, the way they learn could be closer to humans' way of thinking. Researchers have found a common species of fish which is found across Europe, called nine-spined stickleback, to be the first animal to exhibit an important human social learning strategy. The sticklebacks can compare the behaviour of other sticklebacks with their own experience and make choices that lead to better food supplies, found the study published in the 'Behavioral Ecology' journal. According to the researchers, these fish might have an unusually sophisticated social learning capability not yet found in other animals, called a 'hill-climbing' strategy. Lead author Dr Jeremy Kendal of Durham University said: "'Hill-climbing' strategies are widely seen in human society whereby advances in technology are down to people choosing the best technique through social learning and improving on it, resulting in cumulative culture. "Small fish may have small brains but they still have some surprising cognitive abilities. But our results suggest brain size isn't everything when it comes to the capacity for social learning." For the study, 270 fish were caught using dip nets from Melton Brook in Leicester, and housed in aquariums in a laboratory. The fish were split into three experimental groups and one control group. The fish in the experimental groups were given two different learning experiences and two preference tests in a tank with a feeder at each end. First, they were free to explore the feeder at each end during a number of training trials, where one feeder supplied more worms than the other, called the rich feeder. They were then tested to see which feeder they preferred. In the second training trial, those fish that had learned a preference for the rich feeder observed other fish feeding but this time the rich and poor feeders were swapped round with the rich feeder either giving even more worms than the one the fish previously got their food from or giving roughly the same or less. In the second test, the fish were again free to swim around and choose their feeder. Around 75 percent of fish were 'clever' enough to know from watching the other fish that the rich feeder, previously experienced first hand themselves as the poor feeder, gave them the better pay off. In comparison, significantly fewer fish preferred the feeder that appeared to be rich from watching others if they themselves had experience that the alternative feeder would give roughly the same or more food. Dr Kendal said, "These fish are obviously not at all closely related to humans, yet they have this human ability to only copy when the pay off is better than their own

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