GREENWALD, A. G., & DE HOUWER, J. (2017). UNCONSCIOUS CONDITIONING: DEMONSTRATION OF EXISTENCE AND DIFFERENCE FROM CONSCIOUS CONDITIONING. JOURNAL OF EXPERIMENTAL PSYCHOLOGY: GENERAL, 146, 1705-1721. — PREVIEW

Unpronounceable strings of 4 consonants (conditioned stimuli: CSs) were consistently followed by familiar words belonging to one of two opposed semantic categories (unconditioned stimuli: USs). Conditioning, in the form of greater accuracy in rapidly classifying USs into their categories, was found when visually imperceptible (to most subjects) CSs occupied ≥ 58 ms of a 75-ms CS–US interval. When clearly visible CSs were presented in a 375 ms CS–US interval, conditioning was strongly correlated with measures of contingency awareness, and did not occur in the absence of that awareness. These experiments delineated two forms of conditioning: Unconscious conditioning occurred with a brief CS–US interval, with an effectively masked CS, and with no reportable knowledge of the contingent CS–US relation. Conscious conditioning occurred with a substantially longer CS–US interval, a perceptible CS, and with subjects’ reportable knowledge of the contingent CS–US relation.