Semantic context effects when naming Japanese kanji, but not Chinese hànzì.

The process of reading aloud bare nouns in alphabetic languages is immune to semantic context effects from pictures. This is accounted for by assuming that words in alphabetic languages can be read aloud relatively fast through a sub-lexical grapheme-phoneme conversion (GPC) route or by a direct route from orthography to word form. We examined semantic context effects in a word-naming task in two languages with logographic scripts for which GPC cannot be applied: Japanese kanji and Chinese hànzì. We showed that reading aloud bare nouns is sensitive to semantically related context pictures in Japanese, but not in Chinese. The difference between these two languages is attributed to processing costs caused by multiple pronunciations for Japanese kanji.

A paradoxical exposure-duration effect in the Stroop task: temporal segregation between stimulus attributes facilitates selection.

In comparison with the situation in which target and distractor are presented until response, Stroop interference substantially decreases when the target color is removed from the display 150-160 ms after stimulus onset (W. La Heij, N. A. Kaptein, A. C. Kalff, & L. de Lange, 1995; O. Neumann, 1986). Six experiments showed that this paradoxical exposure-duration effect is robust, that it is not due to the target's exposure duration per se, and that it is not due to an increased spatial selectivity of input selection. The present findings support and extend earlier observations that changes in the display during stimulus exposure affect attentional selection. The findings are tentatively interpreted in terms of (a) reduced duration of input selection or (b) facilitation of attribute selection.

Perceptual inertia: spatial attention and warning foreperiod?

Perceptual inertia refers to a potential explanation for the observation that during a short period after stimulus onset, the visual system is insensitive to discriminatory detail. The present study attempted to replicate this empirical result in a simple one-item letter-identification task. The results provided little if any support for the construct of perceptual inertia. In the five experiments reported, evidence consistent with perceptual inertia was only obtained in Experiment 5. However, the Experiment 5 results can at least equally parsimoniously be explained in terms of two standard explanatory factors: an effect of precuing of the target position (selective attention) and foreperiod duration (general preparation).

Word substitution errors in a speeded picture-word task.

Using a speeded-naming variant of the picture-word task, we found that word substitution errors can be elicited in the laboratory. In this variant of the task, participants often responded by saying the word instead of the picture's name. Such word substitution errors are interesting because they allow the evaluation of the relative merits of two broad classes of word production models. We obtained evidence in support of interactive models of word production. In addition, the error data presented evidence that speeded naming taps a late, name retrieval process and that picture naming is semantically mediated.

Stroop interference and disorders of selective attention.

Fourteen patients with right-hemisphere CVA and 8 patients with a left-hemisphere CVA were examined for selective attention deficits using a variant of the Stroop color-word task: the picture-word interference task. Experiments 1 and 2 first compared the performance of the two patient groups and a control group in three tasks of increasing difficulty: picture-word detection, word reading, and picture naming. The results showed that (a) the two patient groups were significantly slower than the control group, but did not differ from each other, and (b) the difference in mean RT between the two patient groups and the control group did not increase with task difficulty. In Experiment 3, the subjects were required to name pictures while ignoring accompanying distractors: nonletter symbols, unrelated words or semantically related words. In this task, the right hemisphere patients showed a much larger semantic interference effect than both the left hemisphere patients and the control group. It is argued that this finding most probably reflects problems in visual selective attention with the right hemisphere patients.

Reducing color-color interference by optimizing selection for action.

Color-color interference refers to the finding that the naming of a target color is hampered by the simultaneous presentation of an incongruent distractor color somewhere else in the visual field. This interference effect has been attributed to an imperfect input selection (selection-for-processing). We test an alternative account in which it is assumed that (a) target and distractor are identified in parallel without mutual interference, (b) the identified target color has to be selected to control the naming response (selection-for-action), and (c) this selection process takes more time and is less accurate in the incongruent condition than in the control conditions. Experiment 1 shows that color-color interference obtained when a target color, presented at the point of fixation, is flanked by incongruent colors. In Experiments 2 and 3, the central target position is indicated by an additional exogenous selection cue. The results show that an abrupt-onset cue, presented at the central target position 160 ms after the onset of the target and distractors, reduces the interference effect. This finding is interpreted as supporting evidence for a selection-for-action account of color-color interference.

Components of Stroop-like interference in word reading.

Previous research has shown that the naming of the picture of, for example, a guitar is substantially delayed when it is accompanied by the name of an object from the same semantic category (e.g., piano) as compared to a nonword control (e.g., xxxxx). La Heij (1988a) has shown that a large part of this Stroop-like interference effect can be attributed to two semantic characteristics of the distractor word: its semantic similarity to the target picture and its semantic relevance in the task at hand. Furthermore, it was argued that the locus of these two interference effects is the process of target-name retrieval. If this is true, semantic interference effects should diminish or disappear when, instead of a picture-naming task, a word-reading task is used. In the present study this prediction is tested. The effects of four distractor characteristics are examined: semantic relatedness, semantic relevance, response set membership and wordness. In contrast to the original picture-naming task only the effect of wordness reached significance. The results of experiments 2 and 3 show that the absence of significant semantic context effects in experiment 1 is not simply due to the fact that a distractor word has less time to affect a word-reading response. The results are taken to support a name-retrieval account of semantic interference in color and picture naming.