In the current study, researchers repeated methods they had used in a 2006 paper, but with one major difference: they used a strain of fruit fly in which they could track the formation of new synapses in the brain. They exposed the flies to a couple of social situations in which learning could occur. In one, male flies were released into an area with "female" flies. However, the females had either already mated, or were actually males to which female pheromones had been applied; both varieties were non-receptive to the males' advances. After a couple of days, when exposed to receptive females, the male flies did not try to mate — presumably they remembered their earlier encounters. They also slept significantly more than flies who did not undergo such an experience. In the second scenario, researchers raised flies either among other flies or in social isolation. Those raised in the socially enriched environment slept considerably more than the isolated flies.
Also surprising was the finding that a mere 16 neurons (out of the 200,000 that make up the fly brain) were involved in the learning process.