The susceptibility to positive framing is what scientists call an irrational bias, and it is very powerful. To better understand why our psyche responds so deeply, Christopher Krupenye, a Duke University graduate student in evolutionary anthropology, and his colleagues Alexandra Rosati of Yale University and Brian Hare of Duke gathered 40 of our closest living relatives — 23 chimpanzees and 17 bonobos — and offered them options for choosing food: either one or two fruits versus a constant number of peanuts. Sometimes the apes were shown one piece of fruit each time they made the selection, but half the time they were given two: positive framing. In other trials, the apes were initially presented two pieces of fruit, but half the time they got only one: negative framing. Regardless of the framing, the apes ended up with an identical quantity of fruit. Yet they were more likely to choose fruit when they were offered the single fruit with its frequent “bonus” than the double fruit with its frequent “loss.”

—Francine Russo
Like Humans, Apes Are Susceptible to Spin