MOST animals can learn to anticipate events. A new study suggests that they may have evolved to do so because the best learners have sex more often and produce significantly more offspring.
Researchers have suspected for decades that animals that could associate food, mates or rivals with external "clues" might have more reproductive success, but no one had ever tested the theory. Now Karen Hollis of Mount Holyoke College in Massachusetts has studied what happens when male blue gourami fish are taught to anticipate the arrival of a female.
Male blue gourami fish guard their territory jealously and attack any fish that approaches. If the intruder turns out to be female, the male abandons his assault and initiates a courtship ritual. Hollis trained seven male fish to expect a mating opportunity by turning on a light just before exposing them to a female. Seven other males served as controls, and ...
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