Stimulus position functions in tachistoscopic identification tasks: Scanning, rehearsal, and order of report

Schwantes, Frederick M.

doi:10.3758/bf03204129

Cited by 18 publications

(20 citation statements)

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“…Similar tasks involving letter identification in horizontal strings have shown that when fixation centres on the medial letter (i.e. where visual acuity is greatest), identification accuracy drops with increasing eccentricity from the centre, except for the exterior letters, where accuracy in identifying targets is similar to that of the medial position (Averbach & Corriell, 1961; Butler, 1975; Butler & Merikle, 1973; Haber & Standing, 1969; Merikle, Coltheart & Lowe, 1971; Schwantes, 1978; Stevens & Grainger, 2003; Wolford & Hollingsworth, 1974).…”

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confidence: 99%

Effect of orthographic processes on letter position encoding

Pitchford

Ledgeway

Masterson

2008

Journal Research in Reading

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We investigate whether orthographic processes influence the identification and encoding of letter position within letter strings. To minimise word-specific effects, we adopt a visual letter search task that requires participants to identify a cued letter target among a random five-letter string. Using this paradigm, previous studies have shown that letter targets to the left are identified faster than those to the right of centre and letter targets in the initial, medial and final positions are identified faster than those in neighbouring positions. While the medial letter advantage is likely to arise from greater visual acuity at the point of fixation, the mechanisms responsible for the left-to-right, and exterior, letter advantage have yet to be determined. We show that: (i) search functions for most letters reflect the directional scanning process required for reading English orthography; (ii) search times are significantly faster for letter targets that appear in the most, compared with the least, frequent position in written words; and (iii) search times correlate significantly with positional letter frequency, especially in the initial and final positions. We propose that a combination of low-level visual, and higher-level orthographic, processes modulate the encoding of letter identities and position in written word recognition. Before a written word can be identified it is commonly agreed that the constituent letters of the word must first be identified and their relative position within the word recognised. This process enables readers of alphabetic scripts to distinguish between words that comprise the same letters but arranged in a different relative order (e.g. 'made' and 'dame' or 'mate' and 'tame'). Past research has suggested that some letter positions are more influential than others for visual word recognition. In particular, the exterior letters of words appear to benefit from faster identification compared with letters forming the interior of written words. This advantage for the processing of exterior letters has been shown over a range of experimental paradigms involving the identification of written words and the processing of written text (e.g.

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confidence: 99%

Effect of orthographic processes on letter position encoding

Pitchford

Ledgeway

Masterson

2008

Journal Research in Reading

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“…The function relating accuracy of report to stimulus position in the string is W-shaped, but there is a strong interaction with order of report or order of cognitive scanning. This causes the normally encountered performance enhancement on the lefthand side (Bryden, 1966;Haber & Standing, 1969;Merikle, Coltheart, & Lowe, 1971;Schwantes, 1978;Smith & Ramunas, 1971). The W shape found is completely in line with the present findings on interference operative in letter recognition in strings.…”

Section: Visual Interference and Letter Recognitionmentioning

confidence: 99%

“…Initial and final letters are less subject to interference, but it is a curious phenomenon that the letters furthest removed from the fovea are best recognized. The robustness of these sensory effects, the foveal acuity effect and lateral interference effects (Bouma, 1970;Merikle, Coltheart, & Lowe, 1971), even after report delays of up to 2 sec (Smith & Ramunas, 1971) seems to leave little room for the effects of control mechanisms (Schwantes, 1978) except for the apparent left-to-right processing when about eight stimuli have to be recalled.…”

Section: Visual Interference and Letter Recognitionmentioning

confidence: 99%

Visual word recognition of three-letter words as derived from the recognition of the constituent letters

Bouwhuis¹,

Bouma²

1979

Perception & Psychophysics

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Word recognition is one of the basic processes involved in reading. In this connection, a model for word recognition is proposed consisting of a perceptual and a decision stage. It is supposed that, in the perceptual stage, the formation of possible words proceeds by separate identification of each of the letters of the stimulus word in their positions. Letter perception is taken to be conditional on position because of interaction effects from neighboring letters. These effects are dependent on both position in the word and retinal eccentricity, which are of particular relevance in reading. The letter-based approach rests on the strong relationship between the results from single-letter recognition in meaningless strings and in real words. Next, in the decision step, the many alternatives generated in the perceptual stage are matched with a vocabulary of real words. It is supposed that the final choice from among the remaining words is made in accordance with the constant ratio rule; frequency effects are not separately incorporated in the model. All predictions of the model are generated by means of data from earlier experiments. Despite being not optimally suited for this purpose, the predictions compare favorably with responses in word-recognition experiments.In this article, a model is reported which describes the recognition of single words of three letters on the basis of the perception of the constituent letters. The model explains more fully the results of an earlier, extensive experiment on the recognition of letters and words carried out by Bouma (1973), which was part of a general investigation of visual processes involved in normal reading. In that experiment, an attempt was made to determine which attributes of words contribute to word recognition, particular attention being paid to explaining the role of initial and final letters of words. In addition, the experiment studied how the perception of a letter in a word related to that of the same letter in a meaningless string of the same length.Full implementation of the model made it necessary to run a supplementary experiment on the recognition of middle letters in meaningless strings. Having already obtained data on initial-and final-letter recognition (Bouma, 1973), quantitative predictions could then be attempted for words consisting of three letters. The experiments were restricted to parafoveally presented words. Under reading-like situations, fixated words can always be correctly perceived and consequently yield no information on the attributes mediating their perception. Since all words in a text shift under the reader's eye, all are at one or more times parafoveal.We owe many thanks to Mr. A. L. M. van Rens who collected the data in the experiments, to Mr. J. C. Jacobs for participating in the tedious phase of the model testing, and to Dr. C. Schiepers, who assisted in the compilation of the word vocabulary.Copyright © 1979 PsychonomicSociety, Inc. 12The manner in which the perception of letters operates in word recognition, according to th...

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“…Generally this function displays a W-shape, i. e., letters near fixation and those at the ends of the array are reported more accurately than letters occupying intermediate positions. In particular, this W-shape function appears relatively insensitive to order-of-report effects (Lefton, 1974;Merikle, Lowe, & Coltheart, 1971;White, 1969 As suggested by Schwantes (1978), there seems to be two kinds of factors which determine the shape of the stimulus position function. One is the structural component factor which includes stimulus retinal locus, relative position within the array, the number of surrounding letters (Butler & Currie, 1986;Goryo & Kawai, 1972;Haber & Standing, 1969;Hershenson, 1969;White, 1969White, , 1970Wolford & Hollingsworth, 1974b).…”

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confidence: 87%

Identification and localization in tachistoscopic partial report

Matsuda

1988

Jpn. Psychol. Res

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The purpose of this study was to investigate the nature of information processing for a briefly presented visual array of Japanese Kana letters. Two experiments were conducted, with the same five subjects, to examine the effects of retinal locus, relative position within an array and lateral masking on partial report performance. Types of errors were also analyzed in order to examine whether these effects were related to identification, localization, or both. Proportions of correct responses, location errors, and item errors as a function of stimulus position were found to suggest that partial report performance does not depend only on the identification processes, but also on the localization processes. These findings were discussed on the basis of dual buffer model proposed by Mewhort, Campbell, Marchetti, and Campbell (1981).

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Stimulus position functions in tachistoscopic identification tasks: Scanning, rehearsal, and order of report

Cited by 18 publications

References 20 publications

Effect of orthographic processes on letter position encoding

Effect of orthographic processes on letter position encoding

Visual word recognition of three-letter words as derived from the recognition of the constituent letters

Identification and localization in tachistoscopic partial report

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