Cold and heavy: grasping the temperature-weight illusion

Area of Science:

• * Neuroscience
• * Human Perception
• * Motor Control

Background:

• * The perceived heaviness of objects can be influenced by factors beyond their actual mass.
• * The temperature-weight illusion (TWI) is a phenomenon where object temperature affects perceived weight.

Purpose of the Study:

• * To investigate the impact of object temperature on the perception of heaviness.
• * To examine how the TWI influences motor actions, specifically grip force and lifting dynamics.

Main Methods:

• * 21 healthy volunteers participated in psychophysical experiments assessing perceived heaviness.
• * Grip-lift experiments recorded fingertip forces during object manipulation.
• * Test objects varied in temperature (cold, neutral, warm) and veridical mass (light, heavy).

Main Results:

• * Cold objects were perceived as approximately 20% heavier than neutral-temperature objects.
• * Grasping and lifting cold objects resulted in ~10% higher peak grip forces and initial force rates.
• * The TWI effect was less pronounced for light or warm objects.

Conclusions:

• * Object cooling enhances apparent heaviness, impacting tactile perception.
• * Temperature significantly modulates the scaling of fingertip forces during object interaction.
• * The TWI demonstrates a clear link between thermal cảm giác and sensorimotor control.