Presents a series of 6 experiments in which Stroop-like effects were generated by modally pure color-color, picture-picture, and word-word stimuli instead of the usual modally mixed color-word or picture-word stimuli. Naming, reading, and categorization tasks were applied. The Stroop inhibition was preserved with these stimuli but unexpectedly showed a semantic gradient only in the naming and not in the reading task. Word categorizing was slower and more interference prone than picture categorizing. These and other results can be captured by a model with two main assumptions: (a) semantic memory and the lexicon are separate, and (b) words have privileged access to the lexicon, whereas pictures and colors have privileged access to the semantic network. Such a model is developed and put to an initial test.

If a word is printed inside the outline drawing of a concrete object, interference patterns as in Stroop research are obtained under the instruction to name the picture or to read the word. Smith and Magee (1980) have shown that these patterns change fundamentally if the naming or reading task is replaced by a categorizing task. Their results seem to corroborate the relative speed hypothesis, which explains Stroop-like interferences by faster processing of the distractor than the target. Two experiments are reported here in which the time course of picture-word interferences was analyzed by a systematically varied stimulus onset asynchrony (SOA) of the two stimulus components in the picture-naming, word-reading, picture-categorizing, and word-categorizing tasks. The results argue against the relative speed hypothesis and suggest a functional internal processing asymmetry between inhibition-immune recoding, effective in word reading and picture categorizing, and inhibition-susceptible recoding in picture naming and word categorizing.

Dyer (1971) investigated the response competition hypothesis of the Stroop phenomenon by temporally separating the color and word components of single stimuli (incongruent, control, and congruent). This line of research was continued in a series of five experiments that generalized Dyer's study: (a) In addition to the color-naming task, a reading task was included; (b) the irrelevant stimulus component was presented before and after the relevant one; (c) the probabilities of congruent and incongruent stimuli were varied; (d) besides color-word/color stimuli, color-color and word-word stimuli were used; and (e) the functional discrimination (color naming or reading) was compared with a sequential discrimination task. The data suggest the following temporal relations: (a) a slow facilitation due to response bias; (b) its inhibitory counterpart; and (c) a fast, strong inhibition with no facilitatory complement that seems to correspond to the usual Stroop conflict but that seems to occur earlier than the response execution stage.

Picture naming has become an important experimental paradigm in cognitive psychology. To name a picture can be considered an elementary process in the use of language. Thus, its chronometric analysis elucidates cognitive structures and processes that underlie speaking. Essentially, these analyses compare picture naming with reading, picture categorizing, and word categorizing. Furthermore, techniques of double stimulation such as the paradigms of priming and of Stroop-like interference are used. In this article, recent results obtained with these methods are reviewed and discussed with regard to five hypotheses about the cognitive structures that are involved in picture naming. Beside the older hypotheses of internal coding systems with only verbal or only pictorial format, the hypotheses of an internal dual code with a pictorial and a verbal component, of a common abstract code with logogen and pictogen subsystems, and the so-called lexical hypothesis are discussed. The latter postulates two main components: an abstract semantic memory which, nevertheless, also subserves picture processing, and a lexicon that carries out the huge amount of word processing without semantic interpretation that is necessary in hearing, reading, speaking and writing.

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