Grasping Perception with Weber's Law

Previous studies have shown that information processing in the visual modality can be parsed into two distinct but interrelated streams: an action stream which engages a dorsal pathway and processes absolute metrics from an egocentric frame of reference; and a perception stream which engages a ventral pathway and processes relative metrics from an allocentric frame of reference. When presented with identical stimuli, each stream engenders different kinematics. The kinematics of action- and perception- driven behaviors have been found to respectively violate and adhere to Weber’s law of human perception. This thesis investigates how the action and perception streams in haptics relate with Weber’s law in grasping and pantomime tasks. Blindfolded participants were given objects to haptically manipulate with one hand and then used the same hand to grasp the object or pantomime the object’s size. Grasp and pantomime behaviors were found to violate and adhere to Weber’s law, respectively.