The size-tuning of the face-distortion after-effect

Area of Science:

• Cognitive Neuroscience
• Visual Perception

Background:

• The face-distortion after-effect (FDAE) demonstrates how adapting to a distorted face influences perception of a normal face.
• Face-selective neurons in the superior temporal sulcus (STS) show size-invariant responses, prompting investigation into FDAE's size tolerance.

Purpose of the Study:

• To investigate the influence of size changes between adapting and test stimuli on the face-distortion after-effect (FDAE).
• To determine if the FDAE is size-tolerant, as predicted by the properties of face-selective neurons.

Main Methods:

• Participants were adapted to distorted upright and inverted faces presented at three different sizes.
• Observers adjusted test faces across the same three sizes to appear normal after adaptation.
• FDAE magnitudes were measured under conditions with identical and varied sizes for adapting and test faces.

Main Results:

• Significant FDAEs were observed across all tested size conditions for both upright and inverted faces.
• FDAEs were approximately twice as strong when adapting and test faces were the same size compared to when sizes differed by one octave.
• Substantial FDAEs persisted even when adapting and test faces differed by two octaves, indicating broad size-tuning.

Conclusions:

• The FDAE is influenced by size differences between adapting and test stimuli, being strongest when sizes match.
• Results suggest that both narrowly and broadly size-tuned neural populations contribute to the FDAE.
• The findings implicate human STS homologous populations with broad size-tuning in mediating the FDAE across larger size variations.