Haptic perception of gravitational and inertial mass

Mass can be perceived in different ways: statically, through gravitational cues; dynamically, through inertialcues; or a combination of both. This article investigates the relationship between these modes of perception. Inthree different experiments, subjects matched masses that were held statically in the hand to masses that wereeither accelerated or decelerated. Accelerated masses were perceived to be smaller than masses of equal physicalmagnitude held statically by a factor of 2. However, decelerated masses were matched veridically to masses heldstatically. This difference remained present when contact duration was made very short. This shows that the shiftin perceived mass is not the result of differences in the information available, but of differences in the mode ofperception (active acceleration vs. passive deceleration). It is hypothesized that this is due to a suppression ofthe perception of applied force in active touch. copyright2010 The Psychonomic Society, Inc.