Cog was a project at the Humanoid Robotics Group of the Massachusetts Institute of Technology. It was based on the hypothesis that human-level intelligence requires gaining experience from interacting with humans, like human infants do. This in turn required many interactions with humans over a long period. Because Cog's behavior responded to what humans would consider appropriate and socially salient environmental stimuli, the robot was expected to act more human. This behavior also provided the robot with a better context for deciphering and imitating human behavior. This was intended to allow the robot to learn socially, as humans do.