Frequency-tagging as a measure of conscious face perception.
Cortex; a journal devoted to the study of the nervous system and behavior June 1, 2026 Audrey Mazancieux, Axel Cleeremans, Adélaïde De Heering
Steady-state visual evoked potentials (SSVEPs) recorded during frequency-tagging can track both objective and subjective conscious perception of faces. In 32 participants viewing image sequences at 6 Hz with faces every fifth image, presented at either 1% or 1.5% contrast, the face-related brain signal at 1.5% contrast was higher during correct gender categorisation than incorrect categorisation and increased linearly with both visibility and confidence ratings. At 1% contrast, no face perception occurred behaviourally, and no brain response to faces was detected. Attention, monitored via a fixation-cross task, related more closely to confidence than visibility. These findings indicate SSVEPs can serve as a marker of conscious perception.