The title says it all, I think. Diego-san is a robot with a big baby face that is supposed to simulate the learning behavior of a one year old human child.
"Its main goal is to try and understand the development of sensory motor intelligence from a computational point of view," [creator Dr. Javier Movellan] explained. "It brings together researchers in developmental psychology, machine learning, neuroscience, computer vision and robotics. Basically we are trying to understand the computational problems that a baby’s brain faces when learning to move its own body and use it to interact with the physical and social worlds."