The Coolidge effect is the phenomenon in which males exhibit renewed sexual interest and arousal when presented with a novel or new sexual partner, even if they have recently ejaculated with a previous partner. This effect is named after an anecdote involving U.S. President Calvin Coolidge and his wife, in which they reportedly visited a farm where a rooster was mating with hens continuously until he was exhausted. When told about this, Mrs. Coolidge remarked that the rooster should be informed about how it's done, to which President Coolidge jokingly commented that he should be informed as well. The Coolidge effect is commonly observed in many species besides humans, and is thought to be a result of evolutionary mechanisms to encourage mating with different partners in order to increase genetic diversity and reproductive success.
