Global surface features contribute to human haptic roughness estimations

Area of Science:

• Psychology
• Haptics
• Sensory Perception

Background:

• Previous research focused on local surface features (e.g., raised dots) and their effect on haptic roughness perception.
• The influence of global surface features (e.g., curved surfaces) on haptic roughness perception remains less understood.

Purpose of the Study:

• To investigate how global surface features affect human haptic roughness perception.
• To determine if exploration method influences roughness estimations.
• To examine the interplay between local and global features in roughness perception.

Main Methods:

• Conducted roughness estimation experiments using haptic stimuli combining local (raised dots) and global (sinusoidal-like curves) features.
• Varied the period of sinusoidal curves to assess the impact of global curvature.
• Tested different exploration methods: direct, indirect, and static.

Main Results:

• Sinusoidal surfaces with smaller periods were perceived as rougher than those with larger periods.
• The perceived roughness was not significantly altered by the direction of finger movement or indirect exploration.
• The impact of global features on roughness perception was modulated by the presence of local features, irrespective of whether the surface was smooth or had raised dots.

Conclusions:

• Global surface features demonstrably contribute to haptic roughness perception.
• Local surface features modulate the weighting of global features in roughness perception.