evolutionary psychology

A new study examines whether or not dogs are able to understand the difference between a human's mistake versus active intent to withhold a treat. Os Tartarouchos/Getty Images hide caption

Software engineer Adriana Kaplan outside her home in South Philadelphia. Kimberly Paynter/WHYY hide caption

Faced with a rat trapped in a restrainer, a free rat opens the trap's door to liberate the trapped animal (while stepping on its head — "very rat-ish behavior," says University of Chicago neurobiologist Peggy Mason). David Christopher/University of Chicago hide caption

A chimpanzee hugs her newborn at Burgers' Zoo in Arnhem, Netherlands, in 2010. Over the course of his long career, primatologist Frans de Waal has become convinced that primates and other animals express emotions similar to human emotions. AFP/Getty Images hide caption

Friend or foe? A California two-spot octopus (Octopus bimaculoides) gives observers the eye at the Marine Biological Laboratory in Woods Hole, Mass. Tom Kleindinst/Marine Biological Laboratory hide caption

A 17-year-old male bonobo eats while his son watches in the Lola Ya Bonobo Sanctuary, Democratic Republic of Congo. Fiona Rogers/Getty Images hide caption

Muslim women praying together in the Istiqlal mosque in Jakarta, Indonesia. Afriadi Hikmal/Getty Images hide caption

A young man records a voice note. A new dating app called Waving lets you swipe right on someone based only off short voice profiles. Getty Images hide caption

Rats and people may rely on "metamemory" in a variety of different ways, scientists say. For a rat, it's likely about knowing whether you remember that predator in the distance; for people, knowing what we don't know helps us navigate social interactions. fotografixx/Getty Images/iStockphoto hide caption

Lily chases sheep for the first time in her shepherd-mix life, at Raspberry Ridge Sheep Farm in eastern Pennsylvania. Several times a year the farm invites dogs for "herding instinct tests." Fred Mogul/WNYC hide caption