Roughness perception across the hands.

Area of Science:

• Neuroscience
• Sensory Perception
• Psychology

Background:

• Tactile perception of surface roughness is influenced by concurrent stimulation of other digits on the same hand.
• Previous research indicates limitations in restricting tactile attention to a single digit.

Purpose of the Study:

• To investigate if tactile attention for roughness is similarly limited when digits on separate hands are stimulated simultaneously.
• To determine if distractor surfaces influence perceived roughness when touched by digits on different hands.

Main Methods:

• Participants performed roughness discrimination tasks using sandpaper surfaces.
• Distractor surfaces were simultaneously touched with a different digit, either on the same or the contralateral hand.
• Perceived roughness of attended surfaces was compared under conditions with and without distractors.

Main Results:

• Roughness perception was generally better on the left hand than the right.
• Perceived roughness of attended surfaces was systematically biased by the roughness of distractor surfaces.
• Attended surfaces were perceived as smoother when paired with smooth distractors and rougher with rough distractors, irrespective of hand.

Conclusions:

• Tactile attention for roughness cannot be easily restricted to a single digit or even a single hand.
• Stimuli at unattended locations do not merely impair perception but actively bias it in the direction of the distractor's properties.