Revisiting the neglected empirical and theoretical work of two pioneers in experimental phenomenology, we tested Enzo Bonaventura' s hypothesis that vividness is the intensive variation of the consciousness of the present, and explored a possible generalization of Renata Calabresi' s hypothesis that such quale may be linked to the brain's intrinsic cycle of similar to 1 s. We tested both hypotheses through experiments using a semantic repetition priming paradigm from the information processing tradition. Participants (N = 81) were asked to read one-/two-noun object descriptions and recall the same target image corresponding to the verbal cue (i.e., apple) following single paired trials in which they were asked to retrieve four types of priming images (perceptually related, i.e., ball; conceptually related, i.e., banana; perceptually & conceptually related, i.e., orange; and unrelated, i.e., accordion). We found that the most vivid visual mental images for the targets, regardless of prime type, image content, or explicit knowledge of the prime-target relations, occurred between 700 and 1,200 ms the window of the conscious present hypothesized by Calabresi. Target images occurring within that time-window were faster (positive priming); beyond that interval, however, they were slower (negative priming). The metric extension of the phenomenological experience tied with either positive or negative priming supports a genuine shift in the perception of image duration either as subjective contraction or expansion, respectively. The time-course points to an event-related potential signature usually linked with verbally evoked visual imagery (the late positive potential) which warrants further empirical confirmation.
