Santino was a misanthrope with a habit of pelting tourists with rocks. As his reputation for mischief grew, he had to devise increasingly clever ways to ambush his wary victims.
Santino learned to stash his rocks just out of sight and casually stand just a few feet from them in order to throw off suspicion. At the very moment that passersby were fooled into thinking that he meant them no harm, he grabbed his hidden projectiles and launched his attack.
Santino was displaying an ability to learn from his past experiences and plan for future scenarios. This has long been a hallmark of human intelligence. But a recently published review paper by the psychologist Thomas Zentall from the University of Kentucky argues that this complex ability should no longer be considered unique to humans.
Santino, you see, is not human. He’s a chimpanzee at Furuvik Zoo in Sweden. His crafty stone-throwing escapades have made him a global celebrity, and also caught the attention of researchers studying how animals, much like humans, might be able to plan their behavior.
Santino is one of a handful of animals that scientists believe are showing a complex cognitive ability called episodic memory. Episodic memory is the ability to recall past events that one has the sense of having personally experienced. Unlike semantic memory, which involves recalling simple facts like “bee stings hurt,” episodic memory involves putting yourself at the heart of the memory; like remembering the time you swatted at a bee with a rolled up newspaper and it got angry and stung your hand.
If an animal can imagine itself interacting with the world in the past via episodic memory – like Santino recalling a failed attack when a human spotted him holding a rock, or you remembering swatting at a bee – it stands to reason that the animal might also be able to imagine itself in the future in a similar scenario, and thus plan its behavior. Santino might opt to hide his rocks, and you might decide to stop antagonizing bees. The ability to represent oneself and one’s actions in the mind’s eye – both in the past in in the future – is what scientists refer to as mental time travel.