Decomposing fear perception: A combination of psychophysics and neurometric modeling of fear perception.

Emotion perception is known to involve multiple operations and waves of analysis, but specific nature of these processes remains poorly understood. Combining psychophysical testing and neurometric analysis of event-related potentials (ERPs) in a fear detection task with parametrically varied fear intensities (N=45), we sought to elucidate key processes in fear perception. Building on psychophysics marking fear perception thresholds, our neurometric model fitting identified several putative operations and stages: four key processes arose in sequence following face presentation - fear-neutral categorization (P1 at 100ms), fear detection (P300 at 320ms), valuation (early subcomponent of the late positive potential/LPP at 400-500ms) and conscious awareness (late subcomponent LPP at 500-600ms). Furthermore, within-subject brain-behavior association suggests that initial emotion categorization was mandatory and detached from behavior whereas valuation and conscious awareness directly impacted behavioral outcome (explaining 17% and 31% of the total variance, respectively). The current study thus reveals the chronometry of fear perception, ascribing psychological meaning to distinct underlying processes. The combination of early categorization and late valuation of fear reconciles conflicting (categorical versus dimensional) emotion accounts, lending support to a hybrid model. Importantly, future research could specifically interrogate these psychological processes in various behaviors and psychopathologies (e.g., anxiety and depression).