Kinesthetic Weight Modulation: The Effects of Whole-Arm Tendon Vibration on the Perceived Heaviness

Kinesthetic illusions, which arise when muscle spindles are activated by vibration, provide a compact means of presenting kinesthetic sensations. Because muscle spindles contribute not only to sensing body movement but also to perceiving heaviness, vibration-induced illusions could potentially modulate weight perception. While prior studies have primarily focused on conveying virtual movement, the modulation of perceived heaviness has received little attention. Presenting a sense of heaviness is essential for enriching haptic interactions with virtual objects. This study investigates whether multi-point tendon vibration can increase or decrease perceived heaviness (Experiment 1) and how the magnitude of the effect can be systematically controlled (Experiment 2). The results show that tendon vibration significantly increases perceived heaviness but does not significantly decrease it, although a decreasing trend was observed. Moreover, the increase can be adjusted across at least three levels within the range of 350-450 g. Finally, we discuss plausible mechanisms underlying this vibration-induced modulation of weight perception.