The planum temporale is a brain area essential for language in humans. In the majority of baboons, this area is larger in the left than in the right hemisphere (shown in red and green, respectively). Baby baboons with this early larger left-than-right PT asymmetry, and only them, will develop a preference for gestural communication with the right hand once they have reached the appropriate age, as shown in red on the left of the graph.
Yannick Becker, Romane Phelipon, Damien Marie, Siham Bouziane, Rebecca Marchetti, Julien Sein, Lionel Velly, et al.
Planum Temporale Asymmetry in Newborn Monkeys Predicts the Future Development of Gestural Communication’s Handedness
2004. Nature Communications 15 (1): 4791 — @HAL