Three Cognitive Markers of Unconscious Semantic Activation

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Science  20 Sep 1996:
Vol. 273, Issue 5282, pp. 1699-1702
DOI: 10.1126/science.273.5282.1699


  • Fig. 1.

    Magnitude of priming as a function of performance on direct measures of prime perceptibility. Each scatterplot point represents an individual subject's average performances at both priming and direct-measure tasks at the indicated prime duration. Each plot shows both a best-fitting cubic regression function with its 95% confidence interval (22) and a superimposed linear regression function. (A and B) Data are from 67-ms SOA masked-priming conditions of experiments reported by Greenwald and Draine (9, 21), and (C) from two additional experiments that included conditions with 50-ms prime durations and 67-ms SOAs (23). Direct measures of prime perceptibility are from separate (later) blocks of trials on which subjects were asked to discriminate either lexicality [whether stimuli presented between premask and postmask were (A) words versus strings of alternating X's and G's (for example, XGXGX) or (C) words versus digits] or semantic meaning [whether masked stimuli were (B) words of pleasant versus unpleasant meaning or male versus female first names]. Sensitivity (d′) values for direct measures were computed by treating one category (for example, words) as signal and the other (for example, digits) as noise, such that guessing word in response to a digit stimulus would be treated as a false alarm. Indirect measure (priming) d′ values were computed by scoring a hit when (say) a male-name response was given on a trial with a male-name prime, and a false alarm when a male-name response was given on a trial with a female-name prime. Printed numerical intercepts are those for the linear regression in the panel; N, number of subjects (scatterplot points).

  • Fig. 2.

    Magnitude of subliminal and supraliminal priming as a function of prime-target SOA. The measure of priming is the same signal-detection measure of sensitivity of target responses to prime meaning shown in Fig. 1. Error bars give 95% confidence intervals. Data are from experiments in which (A) both supraliminal and subliminal priming were measured and (B) only subliminal priming was measured. Prime duration was constant at 50 ms in all experiments. The results show supraliminal priming to be obtained strongly at SOAs as long as 400 ms, whereas subliminal priming decreased sharply at SOAs >100 ms.

  • Fig. 3.

    Magnitude of priming after immediately prior congruent versus incongruent priming trials. Priming magnitudes are presented in the same format as those in Fig. 2. The supraliminal priming data are from nonmasked conditions in which prime duration was 50 ms and SOA was 150 ms, whereas the subliminal priming data are from visually masked conditions that produced largest subliminal priming effects (prime duration = 50 ms, SOA = 67 ms). The results show that for supraliminal priming (but not subliminal priming), a prior incongruent trial weakens priming relative to a prior congruent trial.