The homophone effect during visual word recognition in children: an fMRI study

Functional magnetic resonance imaging was used to investigate the role of phonology in visual word recognition (VWR). A group of children between the ages of 7 and 13 participated in a lexical decision task in which lexical frequency and homophony were manipulated. A significant homophone effect was observed for the high-frequency condition, indicating that phonology does indeed play a significant role in VWR. The brain activation patterns also support this idea in that regions that have been linked to phonological processing, the inferior frontal gyrus and the inferior parietal lobe, also revealed a homophone effect. Additionally, the posterior superior temporal cortex showed a homophone effect; however, this activation is argued to be related to lexical competition generated by the high-frequency homophone via the activation of multiple semantic representations.     

The frequency effect in second-language visual word recognition

A lexical decision experiment with Dutch-English bilinguals compared the effect of word frequency on visual word recognition in the first language with that in the second language. Bilinguals showed a considerably larger frequency effect in their second language, even though corpus frequency was matched across languages. Experiment 2 tested monolingual, native speakers of English on the English materials from Experiment 1. This yielded a frequency effect comparable to that of the bilinguals in Dutch (their L1). These results constrain the way in which existing models of word recognition can be extended to unbalanced bilingualism. In particular, the results are compatible with a theory by which the frequency effect originates from implicit learning. They are also compatible with models that attribute frequency effects to serial search in frequency-ordered bins (Murray & Forster, 2004), if these models are extended with the assumption that scanning speed is language dependent, or that bins are not language specific.     

Item performance in visual word recognition

Standard factorial designs in psycholinguistics have been complemented recently by large-scale databases providing empirical constraints at the level of item performance. At the same time, the development of precise computational architectures has led modelers to compare item-level performance with item-level predictions. It has been suggested, however, that item performance includes a large amount of undesirable error variance that should be quantified to determine the amount of reproducible variance that models should account for. In the present study, we provide a simple and tractable statistical analysis of this issue. We also report practical solutions for estimating the amount of reproducible variance for any database that conforms to the additive decomposition of the variance. A new empirical database consisting of the word identification times of 140 participants on 120 words is then used to test these practical solutions. Finally, we show that increases in the amount of reproducible variance are accompanied by the detection of new sources of variance.     

Perceptual grouping in visual word recognition

Four experiments are presented in which printed texts are read for their meaning. Some of the texts were mutilated by altering the size of selected letters. In Experiments 1, 2, and 3, the number of words mutilated per passage and the number of letters changed per word were both manipulated. In all three experiments, reading was slowed as a function of the number of words changed per passage, while the number of letters changed per word had a much smaller effect. The interaction between the number of words and number of letters changed was not significant in any of the experiments. It is difficult to explain these results merely in terms of changes in the discriminability of letters. In Experiment 2 all uppercase text was used, which argues against an explanation in terms of supraletter features such as word envelope. We propose an explanation in terms of visual attention and the perceptual grouping required prior to feature recognition. The last experiment supports this explanation through the counterintuitive finding that adding letters of intermediate size can improve legibility by allowing grouping processes to associate large and small letters as belonging to the same word object.     

Attentional demands of visual word recognition

Becker's (1976, 1979, 1980, 1985; Becker & Killion, 1977; Eisenberg & Becker, 1982) verification model was used as a framework to investigate the attentional demands of word recognition. In two experiments, a lexical decision task and an auditory probe task were performed in single- and dual-task conditions. Responses to probes were divided into detection and movement measures that indexed the demands of recognition and response output, respectively. In Experiment 1, single- to dual-task decrements in probe detection performance were larger during low-frequency as compared with high-frequency trials. This finding indicates that the attentional demands of word recognition vary with word frequency. These findings were replicated in Experiment 2, which was designed to separate a response compatibility and a capacity interpretation of the results. The findings are interpreted within Becker's verification model.     

Theoretical note: Coordinate systems in visual word recognition

Marr and Nishihara (1978) have made certain recommendations about how representations postulated in a theory of visual information processing should be specified. Using this scheme the paper discusses representations which might be postulated in a model of visual word recognition. A representation is specified in terms of a set of primitives (e.g., word identities or visual features) in combination with a coordinate system. The coordinate systems considered are retinal, spatial (e.g., position on page) word-centred (position in word) and sentence-centred (position in sentence).

Various combinations of primitives and coordinate systems are considered along with how to decide which combinations are actually generated in the process of fluent reading. A tentative model is put forward in which a single processing stage, which starts anew after each saccade, generates a representation with word identities as its primitives and sentence-centred coordinates. Evidence to support such a model which has no intermediate representation with spatial coordinates is briefly reviewed.     

Semantic context and word frequency effects in visual word recognition

Semantic context and word frequency factors exert a strong influence on the time that it takes subjects to recognize words. Some of the explanations that have been offered for the effects of the two factors suggest that context and frequency should interact, and other explanations imply additivity. In a recent study, Schuberth and Eimas reported that context and frequency effects added to determine their subjects' reaction times in a lexical decision (word vs. nonword) task. The present experiment reexamines this question with improved procedures. The data show that context and frequency do interact, with a semantic context facilitating the processing of low-frequency words more than high-frequency words.     

The role of syllabic structure in French visual word recognition

Two experiments are reported in which the processing units involved in the reading of French polysyllabic words are examined. A comparison was made between units following the maximal onset principle (i.e., the spoken syllable) and units following the maximal coda principle (i.e., the basic orthographic syllabic structure [BOSS]). In the first experiment, it took longer to recognize that a syllable was the beginning of a word (e.g., the FOE of FOETUS) than to make the same judgment of a BOSS (e.g., FOET). The fact that a BOSS plus one letter (e.g., FOETU) also took longer to judge than the BOSS indicated that the maximal coda principle applies to the units of processing in French. The second experiment confirmed this, using a lexical decision task with the different units being demarcated on the basis of color. It was concluded that the syllabic structure that is so clearly manifested in the spoken form of French is not involved in visual word recognition.     

The role of external letter positions in visual word recognition

A key issue for any computational model of visual word recognition is the choice of an input coding schema, which is responsible for assigning letter positions. Such a schema must reflect the fact that, according to recent research, nonwords created by transposing letters (e.g., caniso for CASINO ), typically, appear to be more similar to the word than nonwords created by replacing letters (e.g., caviro ). In the present research, we initially carried out a computational analysis examining the degree to which the position of the transposition influences transposed-letter similarity effects. We next conducted a masked priming experiment with the lexical decision task to determine whether a transposed-letter priming advantage occurs when the first letter position is involved. Primes were created by either transposing the first and third letters (démula-MEDULA ) or replacing the first and third letters (bérula-MEDULA). Results showed that there was no transposed-letter priming advantage in this situation. We discuss the implications of these results for models of visual word recognition.     

Modulating semantic feedback in visual word recognition

According to the interactive activation framework proposed by McClelland and Rumelhart (1981), activation spreads both forward and backward between some levels of representation during visual word recognition. An important boundary condition, however, is that the spread of activation from lower to higher levels can be prevented (e.g., explicit letter processing during prime processing eliminates the well-documented semantic priming effect). Can the spread of activation from higher to lower levels also be prevented? This question was addressed with a choice task procedure in which subjects read a prime word and then responded to a target, performing either lexical decision or letter search depending on the color of the target. A semantic context effect was observed in lexical decision, providing evidence of semantic-level activation. In contrast, there was no semantic context effect in the letter search task, despite evidence of lexical involvement: Words were searched faster than nonwords. Further evidence of lexical involvement in the letter search task appeared in Experiment 2 in the form of greater identity priming for words than for nonwords. The results of these experiments are consistent with the conclusion that feedback from the semantic level to the lexical level can be blocked. Hence, between-level activation blocks can be instantiated in both bottom-up and top-down directions.     

Automatic phonological priming in visual word recognition

Theories of visual word recognition have proposed that a word’s phonological properties can be involved in reading visually presented words. Further, it is commonly supposed that this phonological information can be arrived at in at least two ways: (1) by looking it up after identifying the word visually (a lexical route) or (2) by rule-governed translating of the word’s orthographic code (a nonlexical route), Four experiments were conducted to examine whether phonological information is automatically accessed in visual word recognition, and, if so, how this occurs. A priming technique was used with a display sequence of mask, prime, target, mask. Subjects were asked to make written responses to any words that they thought were present, and prime identification was minimal. A facilitatory effect of phonological priming on target identification occurred when primes were homophones of targets. However, no similar facilitation occurred when the prime was a nonword homophone of the target. Further, the homophone priming effect was found irrespective of whether targets followed the spelling-to-sound rules of English. The results suggest that automatic access to phonology can occur in visual word recognition and that it operates by means of a lexical route.     

Homophone interference effects in visual word recognition

In three lexical decision experiments and one progressive demasking experiment, performance on low-frequency heterographic homophones having a high-frequency mate was compared with performance on non-homophone target words with or without high-frequency orthographic neighbours. Robust homophone interference effects were observed in all experiments, as well as inhibitory effects of neighbourhood frequency. When speed-accuracy trade-offs were reduced, the homophone interference effects were found to be additive with effects of high-frequency orthographic neighbours. Furthermore, the size of homophone interference effects increased when pseudohomophone stimuli were presented among the nonwords. These results are tentatively interpreted within the framework of a bi-modal interactive activation model.     

Evidence for word length coding during visual word recognition

In a masked priming procedure manipulating orthographic neighbourhood size, the priming word activates a number of word candidates of which the target could be one. Whether the target is one of the candidates or not determines how quickly it is recognised. However, the efficiency of lexical processing may be markedly less if all possible candidates are activated. One solution to this problem is if the visual system uses prime length information to reduce the number of candidates to a more manageable amount. Here, we investigated in two masked priming experiments whether prime length and orthographic information combine to facilitate target word recognition. In Experiment 1, we showed that the efficiency of visual word recognition is not influenced by the length of primes alone. However, when combined with orthographically related primes, word length coding is preserved. In Experiment 2, we investigated whether length priming affects recognition of short and long words differently. Results showed that only short words benefit from a same-length orthographically related prime, and that the priming effect does not generalise to longer words. These results suggest that the length of a word is not an essential feature in lexical processing, but that it can facilitate recognition by constraining the activation of orthographically related words.     

Recognition intent and visual word recognition

This study adopted a change detection task to investigate whether and how recognition intent affects the construction of orthographic representation in visual word recognition. Chinese readers (Experiment 1-1) and nonreaders (Experiment 1-2) detected color changes in radical components of Chinese characters. Explicit recognition demand was imposed in Experiment 2 by an additional recognition task. When the recognition was implicit, a bias favoring the radical location informative of character identity was found in Chinese readers (Experiment 1-1), but not nonreaders (Experiment 1-2). With explicit recognition demands, the effect of radical location interacted with radical function and word frequency (Experiment 2). An estimate of identification performance under implicit recognition was derived in Experiment 3. These findings reflect the joint influence of recognition intent and orthographic regularity in shaping readers’ orthographic representation. The implication for the role of visual attention in word recognition was also discussed.     

Orthographic neighbors and visual word recognition

Two lexical decision experiments, using words that were selected and closely matched on several criteria associated with lexical access, provide evidence of facilitatory effects of orthographic neighborhood size and no significant evidence of inhibitory effects of orthographic neighborhood frequency on lexical access. The words used in Experiment 1 had few neighbors that were higher in frequency. In Experiment 2, the words employed had several neighbors that were higher in frequency. Both experiments showed that words possessing few neighbors evoked slower responses than those possessing many neighbors. Also, in both experiments, neighborhood size effects occurred even though words from large neighborhoods had more potentially interfering higher-frequency neighbors than words from small neighborhoods.     

On access representation in visual word recognition: The temporal separation technique

Summary This paper examines the evidence for an access representation based on the initial part of the word. A temporal separation technique, which presents test words in two parts, was used, and varied as to whether the first part included two, three, or four initial letters of a word. In contrast with previous studies, word-frequency effects were used to assess whether access had occurred from that initial part. Experiment 1 (in English) tested the validity of the temporal separation technique, and showed that it does impose an input segmentation. Experiments 2 (in English) and 3 (in Spanish) examined whether access to a monomorphemic word is achieved, using word frequency as a diagnostic of access. The implications of the findings for the notion of a partial input representation for access are discussed.     

Letter legibility and visual word recognition

Word recognition performance varies systematically as a function of where the eyes fixate in the word. Performance is maximal with the eye slightly left of the center of the word and decreases drastically to both sides of thisoptimal viewing position. While manipulations of lexical factors have only marginal effects on this phenomenon, previous studies have pointed to a relation between the viewing position effect (VPE) and letter legibility: When letter legibility drops, the VPE becomes more exaggerated. To further investigate this phenomenon, we improved letter legibility by magnifying letter size in a way that was proportional to the distance from fixation (e.g., TABLE). Contrary to what would be expected if the VPE were due to limits of acuity, improving the legibility of letters has only a restricted influence on performance. In particular, for long words, a strong VPE remains even when letter legibility is equalized across eccentricities. The failure to neutralize the VPE is interpreted in terms of perceptual learning: Since normally, because of acuity limitations, the only information available in parafoveal vision concerns low-resolution features of letters; even when magnification provides better information, readers are unable to make use of it.     

The KEY to the ROCK: Near-homophony in nonnative visual word recognition

To test the hypothesis that native language (L1) phonology can affect the lexical representations of nonnative words, a visual semantic-relatedness decision task in English was given to native speakers and nonnative speakers whose L1 was Japanese or Arabic. In the critical conditions, the word pair contained a homophone or near-homophone of a semantically associated word, where a near-homophone was defined as a phonological neighbor involving a contrast absent in the speaker’s L1 (e.g., ROCK-LOCK for native speakers of Japanese). In all participant groups, homophones elicited more false positive errors and slower processing than spelling controls. In the Japanese and Arabic groups, near-homophones also induced relatively more false positives and slower processing. The results show that, even when auditory perception is not involved, recognition of nonnative words and, by implication, their lexical representations are affected by the L1 phonology.     

A multistream model of visual word recognition

Four experiments are reported that test a multistream model of visual word recognition, which associates letter-level and word-level processing channels with three known visual processing streams isolated in macaque monkeys: the magno-dominated (MD) stream, the interblob-dominated (ID) stream, and the blob-dominated (BD) stream (Van Essen & Anderson, 1995). We show that mixing the color of adjacent letters of words does not result in facilitation of response times or error rates when the spatial-frequency pattern of a whole word is familiar. However, facilitation does occur when the spatial-frequency pattern of a whole word is not familiar. This pattern of results is not due to different luminance levels across the different-colored stimuli and the background because isoluminant displays were used. Also, the mixed-case, mixed-hue facilitation occurred when different display distances were used (Experiments 2 and 3), so this suggests that image normalization can adjust independently of object size differences. Finally, we show that this effect persists in both spaced and unspaced conditions (Experiment 4)—suggesting that inappropriate letter grouping by hue cannot account for these results. These data support a model of visual word recognition in which lower spatial frequencies are processed first in the more rapid MD stream. The slower ID and BD streams may process some lower spatial frequency information in addition to processing higher spatial frequency information, but these channels tend to lose the processing race to recognition unless the letter string is unfamiliar to the MD stream—as with mixed-case presentation.