The high-level basis of body adaptation

Area of Science:

• Perceptual psychology
• Visual neuroscience
• Object recognition

Background:

• Prolonged visual exposure (adaptation) to body shapes induces aftereffects, altering subsequent perception.
• These aftereffects cause perceived bodies to appear wider or thinner than their actual dimensions.

Purpose of the Study:

• To investigate the influence of stimulus orientation on body shape aftereffects.
• To determine the extent to which aftereffects transfer across different orientations.
• To differentiate the roles of high-level object-based versus low-level retinotopic mechanisms.

Main Methods:

• Two experiments were conducted using visual adaptation paradigms.
• Participants adapted to bodies of a specific orientation and then viewed test stimuli at different orientations.
• Stimulus orientation was rotated by 90° between adaptation and test phases; stimulus size was varied in Experiment 2.

Main Results:

• Aftereffects were strongest when adaptation and test stimuli shared the same orientation.
• Perceived distortion axis shifted with stimulus orientation, indicating orientation-dependent processing.
• Significant aftereffect transfer (58% in Experiment 1) occurred across orientations, increasing when stimulus sizes differed.

Conclusions:

• Body shape aftereffects are primarily mediated by high-level, object-based visual processes.
• Low-level retinotopic mechanisms play a minimal role in these aftereffects.
• The contribution of low-level mechanisms diminishes further when adaptation and test stimuli vary in size.