Social transmission of maladaptive information in the guppy

Many animals are capable of learning from others, a process referred to as social learning. There is little doubt that a capacity for social learning is an adaptation and that it typically results in adaptive behavior. What is less clear is whether there are circumstances under which social learning can result in the transmission of outdated, inappropriate, or maladaptive information. Here we report an experimental study that investigated the social learning and transmission of maladaptive foraging information through small social groups of guppies, Poecilia reticulata. This experiment used a transmission chain design in which fish in small founder groups were trained to take either an energetically costly circuitous route to a feeder or a less costly short route, with trained founder members gradually replaced by untrained conspecifics. Three days after all the founders had been removed, the behavioral traditions of groups of untrained fish were still strongly influenced by their founder's behavior. Moreover, the rate at which untrained subjects that shoaled with founder conspecifics trained to take the long route learned to take the short route was significantly slower than for fish foraging alone. The results provide unequivocal evidence that maladaptive information can be socially transmitted through animal populations acid imply that socially learned information can inhibit learning of the optimal behavior pattern.