Top-down modulation of shape and roughness discrimination in active touch by covert attention

Area of Science:

• Cognitive Psychology
• Neuroscience
• Sensory Perception

Background:

• Top-down mechanisms like attention are crucial for selecting relevant sensory information.
• Understanding how attention modulates active touch perception is essential for explaining sensory processing limitations.

Purpose of the Study:

• To investigate the impact of covert attention on the perception of 3D object features (shape and roughness) during active touch.
• To determine if task expectations modulate tactile discrimination thresholds.

Main Methods:

• Participants actively explored two objects sequentially, focusing on shape and roughness.
• Task expectation was manipulated by varying the frequency of shape versus roughness judgment trials (20%, 50%, 80%).
• Discrimination thresholds for shape and roughness were measured under different expectation conditions.

Main Results:

• Discrimination thresholds for both shape and roughness perception were significantly higher when the task was unexpected.
• Perceptual performance was better when participants expected a specific judgment compared to unexpected tasks.

Conclusions:

• Active touch perception is modulated by task expectations, similar to passive touch.
• Feature-selective covert attention, influenced by expectations, plays a role in active tactile sensory processing.