Fearful expressions facilitate perceptual dominance of low spatial frequency information in visual awareness

The human brain optimises cognitive resource allocation to enhance the processing speed and efficiency of vital information for better survival and adaptation in response to threat signals. Previous studies found that fearful expressions, as visual cues signalling threats, can not only have advantages in entering and remaining in awareness, but also enhance subsequent perceptual processing of low-spatial-frequency (LSF) information. However, it remains unknown whether the enhanced perceptual processing of LSF induced by fearful expressions also grants LSF information a competitive advantage in awareness. To this end, we employed a binocular rivalry paradigm to measure awareness of Gabor patches with low or high spatial frequencies following the rapid priming of fearful versus neutral expressions. The results revealed that the relative dominance of LSF over high-spatial-frequency (HSF) Gabor patches was markedly heightened following brief exposure to fearful compared with neutral expressions. This effect was found for both upright and inverted expressions, indicating it is independent of face configuration. Our study thus suggests a feature-based perceptual optimisation mechanism with evolutionary significance, potentially optimising cognitive resource allocation in threatening situations.