The relationship between the objective identification threshold and priming effects does not provide a definitive boundary between conscious and unconscious perceptual processes

The Objective Threshold/Strategic Model (OT/S) proposes that strong, qualitative inferences of unconscious perception can be made if the relationship between perceptual sensitivity (typically priming effects) and stimulus visibility is nonlinear and nonmonotonic. The model proposes a nadir in priming effects at the objective identification threshold (identification d′ = 0). These predictions were tested with masked semantic priming and repetition priming of a lexical decision task. The visibility of the prime stimuli was systematically varied above and below the objective identification threshold. The obtained relationship between prime visibility and priming facilitation was nonlinear, but the results failed to confirm a nadir in priming effects at the objective identification threshold. We conclude that the objective identification threshold does not necessarily indicate the point where presumably unconscious priming effects might be inhibited by conscious cognitive processes.