Daniel Kruger, an evolutionary psychologist at the University of Michigan, believes cuteness can be explained through something called life history theory. It’s a framework for understanding how natural selection may have shaped a species’ anatomy and behavior at different stages of life.

At birth, many species must fend for themselves, such as the brush turkeys of Australia and Indonesia. Juveniles hatch fully feathered and virtually ready to fly. Other species, particularly mammals, are born fairly helpless and rely on parental care for an extended period.

“Every organism has limited resources, so how are we going to allocate that effort? It’s always a trade-off,” says Kruger. “We see a convergence of high intelligence and slower development. … There is a need for parental care because the brain is developing over a longer period of time.”

Or, as his University of Michigan colleague Stephanie Preston puts it: “If there’s pressure to evolve a bigger brain, the brain can only get so big and still make it through the birth canal. So you come out with the brain not fully finished, still needing to develop, and you need more parental care.”

Preston, a professor of psychology and director of the Ecological Neuroscience Lab, studies how and why behaviors evolved in both humans and other species. She notes that some form of kindchenschema turns up “across the board” in social mammals whose young require parental care.

Read the full article at Discover.