Richard L. Abrams

Three Cognitive Markers of Unconscious Semantic Activation

A “response window” technique is described and used to reliably demonstrate unconscious activation of meaning by subliminal (visually masked) words. Visually masked prime words were shown to influence judged meaning of following target words. This priming-effect marker was used to identify two additional markers of unconscious semantic activation: (i)the activation is very short-lived (the target word must occur within about 100 milliseconds of the subliminal prime); and (ii) unlike supraliminal prime-target pairs, a subliminal pair leaves no memory trace that can be observed in response to the next prime-target pair. Thus, unconscious semantic activation is shown to be a readily reproducible phenomenon but also very limited in the duration of its effect.

Parts Outweigh the Whole (Word) in Unconscious Analysis of Meaning

In unconscious semantic priming, an unidentifiable visually masked word (the prime) facilitates semantic classification of a following visible related word (the target). Three experiments reported here provide evidence that masked primes are analyzed mainly at the level of word parts, not whole-word meaning. In Experiment 1, masked nonword primes composed of subword fragments of earlier-viewed targets functioned as effective evaluative primes. (For example, after repeated classification of the targets angel and warm, the nonword anrm acted as an evaluatively positive masked prime.) Experiment 2 showed that this part-word processing was potent enough to oppose analysis at the whole-word level. Thus, smile functioned as an evaluatively negative (!) masked prime after repeated classification of smut and bile. Experiment 3 found no priming when masked word primes contained no parts of earlier targets. These results suggest that robust unconscious priming (a) is driven by analysis of part-word information and (b) requires previous classification of visible targets that contain the fragments later serving as primes. Contrary to a widely held view, analysis of subliminal primes appears not to function at the level of analysis of complete words.

Subliminal words activate semantic categories (not automated motor responses)

Semantic priming by visually masked, unidentifiable (“subliminal”) words occurs robustly when the words appearing as masked primes have been classified earlier in practice as visible targets. It has been argued (Damian, 2001) that practice enables robust subliminal priming by automatizing learned associations between words and the specific motor responses used to classify them. Two experiments demonstrate that, instead, the associations formed in practice that underlie subliminal priming are between words and semantic categories. Visible words classified aspleasant or unpleasant in practice with one set of response key assignments functioned later as subliminal primes with appropriate valence, even when associations of keys with valences were reversed before the test. This result shows that subliminal priming involves unconscious categorization of the prime, rather than just the automatic activation of a practiced stimulus-response mapping.

Priming of semantic classifications by novel subliminal prime words.

Four experiments demonstrate category congruency priming by subliminal prime words that were never seen as targets in a valence-classification task (Experiments 1, 2, and 4) and a gender-classification task (Experiment 3). In Experiment 1, overlap in terms of word fragments of one or more letters between primes and targets of different valences was larger than between primes and targets of the same valence. In Experiments 2 and 3, the sets of prime words and target words were completely disjoint in terms of used letters. In Experiment 4, pictures served as targets. The observed subliminal priming effects for novel primes cannot be driven by partial analysis of primes at the word-fragment level; they suggest instead that primes were processed semantically as whole words contingent upon prime duration.

Unconscious semantic priming in the absence of partial awareness

In a recent paper in Psychological Science, Kouider and Dupoux reported obtaining unconscious Stroop priming only when subjects had partial awareness of the masked distractor words (i.e., could consciously perceive subword features that enabled reconstruction of whole words). Kouider and Dupoux conjectured that semantic priming occurs only when such partial awareness is present. The present experiments tested this conjecture in an affective categorization priming task that differed from Kouider and Dupouxs in using masked distractors that subjects had practiced earlier as visible words. Experiment 1 showed priming from practiced words when subjects had no partial awareness of those words. Experiment 2 showed that, in the absence of partial awareness, practiced words yielded priming but not-practiced words did not. Experiment 3 corroborated Experiment 1 and 2s results using a different test of partial awareness. These results suggest that unconscious processing (rather than partial awareness) of subword elements drives masked semantic priming by practiced words.

Influence of Category Size and Target Set Size on Unconscious Priming by Novel Words

In support of their argument that unconscious priming by novel words is critically influenced by target set size, Kiesel, Kunde, Pohl, and Hoffman (2006) report priming from novel words when target sets were large but not when they were small. The present experiment examined the possibility that target set size interacts with category size. (In both experiments in Kiesel et al., category size was large.) In the present experiment, with a small target set, novel-word priming did occur when categories were small (farm animals, fruits) but not when categories were large (larger or smaller than a computer monitor). This finding suggests that, contrary to the position advanced by Kiesel et al., priming when target sets are small involves a mechanism other than preactivation of perceptual features belonging to the target set.

Orthographic overlap and category size in unconscious category priming: comment on experiment 1c of Van den Bussche and Reynvoet (2007).

Van den Bussche and Reynvoet (2007, Experiment 1) report unconscious priming of comparable magnitude from novel words belonging to small and large categories, evidence that they interpret as demonstrating independence from category size of priming that involves semantic analysis. Three experiments raise the possibility that the findings in Experiment 1c of Van den Bussche and Reynvoet reflect subword processing, not semantic analysis. In Experiments 1 and 2, priming was obtained from primes and targets that shared approximately the same degree of subword features as in Experiment 1c of Van den Bussche and Reynvoet, but no priming occurred when sharing of features was minimized. Experiment 3 demonstrated priming driven by subword features when those features were set in opposition to whole-word meaning. These results indicate that orthographic overlap must be considered a potentially important confound in findings that ostensibly support priming mediated by semantic analysis.