An anonymous reader sends an article from Quanta Magazine about research into individuality — how behavior varies (or doesn't) when genetics and environment are as similar as possible
. Scientists are taking various strains of fruit fly that are genetically almost identical (the result of extreme inbreeding) and raising them alone in environments that are exact copies of each other. Then they run the fruit flies through a series of decision-making tests to see how varied their responses are. Some fruit fly strains show a high degree of variance for tasks like navigating a maze. Other strains show almost no variance, suggesting there's a genetic component to individuality.
The scientists also found that manipulating a certain set of neurons in the fruit flies's brains could increase the variation in choices they make. One theory suggests that evolution tends to select for genes that increase individuality by making it more difficult for predators to predict what the prey will do next.