Influence of shape on the haptic size aftereffect

Area of Science:

• Psychology
• Neuroscience
• Haptics

Background:

• A prior study demonstrated a significant haptic size aftereffect using a size bisection task.
• This aftereffect occurs when adaptation to a large object causes subsequent smaller objects to feel even smaller, and vice versa.

Purpose of the Study:

• To investigate if the strength of the haptic size aftereffect is influenced by object shape.
• To determine if the aftereffect differs when adaptation and test stimuli share the same shape versus different shapes.

Main Methods:

• Four experimental conditions were used to measure the haptic aftereffect.
• Participants were adapted to either spheres or tetrahedra and then tested with spheres and tetrahedra.

Main Results:

• The haptic aftereffect was significantly stronger when the adaptation and test stimuli were identical in shape.
• A weaker aftereffect was observed when the shapes of adaptation and test stimuli differed.
• This indicates that shape plays a crucial role in the haptic size aftereffect.

Conclusions:

• The findings support the concept of haptic shape-size aftereffects, where shape is a critical factor, not just size.
• The influence of shape suggests involvement of higher cortical areas, ruling out peripheral receptor adaptation.
• Individual differences exist in the geometric properties used for haptic size judgments, despite participant consistency.