1 in 5 people can ‘hear’ flashes of light. This is a form of synesthesia, where 2 or more sensory experiences are cross- wired, much like seeing colors when you hear certain musical notes or hearing notes when you see flashing lights. It’s also more common in trained musicians and might account for the appeal of having strobe lights at raves. (, )

Monkeys can learn to use money. Capuchins that were taught to exchange silver discs for treats began budgeting for foods they liked, buying more of something when the price dropped, and started gambling. Eventually, there was an incident where ‘money’ was stolen, and the rich monkeys even figured out they could pay each other for sex. (, )