Are coarse scales sufficient for fast detection of visual threat?

It has recently been suggested that low-spatial-frequency information would provide rapid visual cues to the amygdala for basic but ultrarapid behavioral responses to dangerous stimuli. The present behavioral study investigated the role of different spatial-frequency channels in visually detecting dangerous stimuli belonging to living or nonliving categories. Subjects were engaged in a visual detection task involving dangerous stimuli, and subjects' behavioral responses were assessed in association with their fear expectations (induced by an aversive 90-dB white noise). Our results showed that, despite its crudeness, low-spatial-frequency information could constitute a sufficient signal for fast recognition of visual danger in a context of fear expectation. In addition, we found that this effect tended to be specific for living entities. These results were obtained despite a strong perceptual bias toward faster recognition of high-spatial-frequency stimuli under supraliminal perception durations.