Shifting focus: Does adaptation to new configural face information alter fixation behavior?

Face adaptation research shows that viewing a manipulated face biases the perception of subsequent faces. This study examined whether these adaptation effects are also reflected in eye movements. Participants viewed highly compressed, elongated, or non-manipulated adaptor faces before selecting the most veridical test image, while their eye movements were recorded to assess fixation durations and spatial distributions. The results confirmed robust behavioral adaptation effects, replicating previous findings. On the adaptor faces, fixations were shorter for manipulated images, suggesting rapid detection of distortion. Spatially, compressed adaptors drew fixations to the nose, while elongated ones shifted gaze to the upper face. Notably, an interaction pattern in test face fixation durations emerged; however, conflicting results from frequentist and Bayesian analyses warrant a cautious interpretation. The pattern, where participants fixated longer on slightly compressed faces after adapting to elongated ones, suggests fixation duration may not track the adaptation effect directly. Instead, it might reflect the processing load associated with resolving the induced perceptual conflict. While spatial fixation patterns did not mirror behavioral adaptation, fixation duration may be a sensitive, implicit measure of adaptation's cognitive consequences, a potential that future research should explore.