Humans' folk physics is sensitive to physical connection and contact between a tool and reward

Three experiments examined adult humans' folk physics (i.e., their naturally occurring understanding of the physical world) using variations of rope-and- banana problems that are used to study chimpanzees' folk physics. When presented with symbolic versions of these problems, the participants' choices were controlled by both the presence of a physical connection between a tool and reward (unlike chimpanzees' choices) and the degree of contact between these objects (more like what controls chimpanzees' choices). Similar results were obtained when actual ropes and bananas were used. We speculate that the degree of contact between a tool and a reward influenced people's behavior because contact and physical connection are often correlated in people's natural environments and because contact is a reliable predictor of physical connection. (C) 2007 Elsevier B.V.. All rights reserved.