Comfort as a Determinant of the Location of Critical Boundaries in the Act of Reaching

This chapter examines the possibility that actors attempt to avoid extreme movements and awkward postures that might produce some strain or discomfort. It focuses on the transition between arm-and-torso and standing reaches. The location of participants’ preferred critical boundaries was determined by having them reach for objects at placed various distances and observing the reach mode used. The participants were instructed to reach for objects at the same distances using a seated reach and then rate their level of discomfort or effort experienced during the reach. Actors attempt to avoid extreme movements, predicts that there should be a marked increase in a participant’s discomfort/effort judgments at the location of each participant’s preferred critical boundary.