A visual illusion that causes adults to misjudge objects’ sizes doesn’t affect young children, a new study finds.

Study of hunter-gatherer community in Tanzania shows that, across human groups, mating criteria vary. (p. 14)

Colorful birds possibly raised for ceremonial and trade purposes long before Spanish arrival

For chimpanzees living in a forest surrounding the village of Bossou in Guinea, cracking nuts is a serious task with important steps. They are: First, lug large rocks to a spot near a nut-bearing tree, such as an oil palm. Next, gather the nuts and place them on the rocks. Then, obtain a smaller, graspable rock. Finally, smash the armored treats and let the shells fly. As clutches of apes pound away with devastating precision, these nut bashers create an unholy din akin to a human rock band. In fact, these West African chimps rock out in a surprising way. In this corner of the jungle, chimp... (p. 24)

A 37-million-year-old jaw suggests the famous fossil Darwinius does not, as had been suggested, fill a gap in human evolution.

Island-dwelling pygmies provide contested evidence that body size shrinks as mortality rates climb.

Macaque mothers and infants engage in emotional interactions similar to those of human moms and their babies, a new study suggests. (p. 15)

African hominid fossils, including a partial skeleton, reveal a surprising mix of features suitable for upright walking and tree climbing 4.4 million years ago. (p. 9)

Two ancient populations laid the genetic foundation for most people now living in India, a new DNA study suggests.

New, higher prevalence rates for certain mental disorders fuel a debate over how to revise psychiatric diagnoses. (p. 5)