Two studies of development of spatial representation with two dimensions found that children as young as five years use the same two independent dimensions in fine-grained spatial coding of location in a circle as adults use--radius and angle. The adult pattern, where angle as well as radius is coded hierarchically, emerges by nine years. (HTH)

Previous studies have found that an object can be categorized faster at a basic level (hammer) than at either a subordinate (club hammer) or a superordinate level (tool). While some attribute this result to basic categories having more distinctive attributes, other factors might cause this result. For example, basic categories routinely have…