This study compared the interfering effects of various word parts on performance of the Stroop task. In different conditions, the first, middle, and last two letters of a color word formed color patches. In other conditions, random letters were attached to these word parts. In a control condition, entire words formed the color patches. While no condition produced as much interference as the control condition, the first part of a color word interfered with color naming more than other word parts. The addition of unrelated letters had little or no effect on the interference produced by the first part of a word. The results are consistent with suggestions that word perception often involves the activation of an articulatory motor program which is initiated by the first part of the word.Several lines of research on word processing indicate that competent readers do not encode words by a letter-by-letter process. Research by Reicher (1969) and Wheeler (1970) demonstrated that subjects recognized single letters in tachistoscopically presented words with significantly greater accuracy than when the letter was embedded in randomly generated strings of letters or when the letter appeared by itself. One might conclude that competent readers process words as single units. Another interpretation. often suggested from psycholinguistic approaches to reading (Smith. 1973) and recently supported by experimental evidence (Thompson & Massaro. 1973). posits that a competent reader capitalizes on the redundancy of probable relations between letters in English orthography. That is. the probabilistic nature of spelling patterns. or the fact that certain letters occur together frequently. allows the competent reader to intelligently guess that a letter will occur in a given letter sequence. As an obvious example. the letter "q" imposes severe restrictions on the subsequent few letters in a word. If words are considered as left-to-right sequences of letters. then the first letter imposes more constraints and thus provides more information than subsequent letters. If letters are perceived in a left-to-right sequence, then the first letter should be the most important.Empirical support for this description of the reading process is provided by a recent study by Eriksen and Eriksen (1974 sequentially presented in two segments such that one of the letters was delayed by an interval of 0 to 500 msec, and subjects were required to pronounce the words as rapidly as possible. It was found that delay of the first letter was detrimental to performance. while delay of any of the other letters facilitated performance. Since this facilitation was dependent on whether the first letter had a constant pronunciation that was not dependent on the subsequent letters. it was concluded that the perceptual processing was associated with the activation of a motor program for pronouncing the word.The purpose of the present study was to test the reported importance of the first letters in processing words using several variations of the Stroop test. If the fir...

No abstract

No abstract

Contemporary feature models of form perception have typically defined visual similarity in terms of shared (or discordant) sets of points. Two experiments tested the adequacy of this definition. 41 a same/different task, subjects were required to detect a single "different" form in displays of two. four, or six forms. In separate conditions, the "different" form was produced by various geometrie transformations, where the number of discordant points could be held constant for some of those transformations. The first experiment compared the detectability of three transformations: deletion of an end-of-a-line segment, a break in continuity, and a mirror-image reversal. Reversals were detected most rapidly and accurately, with performance independent of display size. Although breaks and deletions produced the same number of discordant points, breaks were detected more rapidly and accurately. The second experiment tested whether the better detectability of reversals was due to a greater number of discordant points or to changes in the orientation of diagonal lines. The results indicated that entire displays can be rapidly organized (in "parallel") on the basis of line orientations. In general, the experiments suggest that the similarity of forms may depend upon the transformations by which they are related rather than their common features.

No abstract