Repetition priming in an auditory lexical decision task: Effects of lexical status

The effect of lexical status on the time course of repetition priming was examined in an auditory lexical decision task. Words and nonwords were repeated at lags of 0, 1, 4, and 8 items (Experiment 1A) and 0, 2, 4, and 8 items (Experiment 1B). The pattern of repetition effects differed for words and nonwords in that repetition priming for nonwords at lag 0 was significantly greater than for words. The magnitude of this effect decreased when one or more items intervened. A second experiment, replicating Experiment 1A with visual presentation, clarified that the greater magnitude of repetition priming for nonwords at lag 0 is unique to the auditory modality. This finding suggests that in the course of forming a stable perceptual representation, the details of the acoustic/phonological information of an auditory stimulus are more readily available for nonwords than for words. The capacity to carry this phonological information is limited, however, and can only be maintained until another stimulus is encountered.     

Lexical and sublexical processes in the perception of transposed-letter anagrams

Evidence from priming and lexical decision tasks suggests that nonwords created by transposing adjacent letter pairs (TL nonwords) are very effective in activating lexical representations of their base words, because the process of orthographic matching tolerates minor changes in letter position. However, this account disregards the possible role of sublexical processing in reading. TL nonwords are perceptually ambiguous, with lexical and sublexical processing giving rise to conflicting interpretations. The consequences of this ambiguity were investigated in a lexical decision experiment with primes that were either high or low bigram frequency TL versions of target words. Priming effects were much larger for low BF primes (e.g., pucnh-PUNCH) than for high BF primes (e.g., panit-PAINT). This finding is interpreted as evidence that lexical activation can be inhibited by competing output resulting from sublexical processing of TL letter string. We conclude that phonological processing is an important determinant of responses to TL stimuli, and we consider how this interpretation might be accommodated within the dual-route cascaded (DRC) model of word recognition.     

Cascaded versus noncascaded models of lexical and semantic processing: the turple effect

The density of the orthographic neighborhood surrounding an item has been shown to have an inhibitory effect for nonwords in a lexical decision experiment. Four experiments are reported investigating whether a similar pattern holds for a semantic categorization task (animal vs. non-animal). In the first experiment, no effects of neighborhood density were found for nonexemplars, whether they were words or nonwords. The absence of any inhibitory effect for nonwords implies that close orthographic neighbors are ignored. However, the second experiment showed that if the nonword has a neighbor that is an animal name (eg., turple), an interference effect is observed, implying that neighbors do exert an effect if they have the right semantic properties. The same items showed no additional interference in lexical decision. These results suggest the involvement of semantic properties very early in the processing cycle. A cascaded processing system monitoring activation in semantic features can explain these results, but cannot explain the frequency effect observed for nonexemplar words or the fact that variation in density is irrelevant when one of the neighbors is an exemplar. It is argued that existing models of semantic categorization must be extended to accommodate these results.     

Lexical and sublexical processes in the perception of transposed-letter anagrams

Evidence from priming and lexical decision tasks suggests that nonwords created by transposing adjacent letter pairs (TL nonwords) are very effective in activating lexical representations of their base words, because the process of orthographic matching tolerates minor changes in letter position. However, this account disregards the possible role of sublexical processing in reading. TL nonwords are perceptually ambiguous, with lexical and sublexical processing giving rise to conflicting interpretations. The consequences of this ambiguity were investigated in a lexical decision experiment with primes that were either high or low bigram frequency TL versions of target words. Priming effects were much larger for low BF primes (e.g., pucnh–PUNCH) than for high BF primes (e.g., panit–PAINT). This finding is interpreted as evidence that lexical activation can be inhibited by competing output resulting from sublexical processing of TL letter string. We conclude that phonological processing is an important determinant of responses to TL stimuli, and we consider how this interpretation might be accommodated within the dual-route cascaded (DRC) model of word recognition.     

Do transposed-letter similarity effects occur at a prelexical phonological level?

Nonwords created by transposing two letters (e.g., RELOVUTION) are very effective at activating the lexical representation of their base words (Perea & Lupker, 2004). In the present study, we examined whether the nature of transposed-letter (TL) similarity effects was purely orthographic or whether it could also have a phonological component. Specifically, we examined transposed-letter similarity effects for nonwords created by transposing two nonadjacent letters (e.g., relovución-REVOLUCION) in a masked form priming experiment using the lexical decision task (Experiment 1). The controls were (a) a pseudohomophone of the transposed-letter prime (relobución-REVOLUCION; note that B and V are pronounced as /b/ in Spanish) or (b) an orthographic control (relodución-REVOLUCION). Results showed a similar advantage of the TL nonword condition over the phonological and the orthographic control conditions. Experiment 2 showed a masked phonological priming effect when the letter positions in the prime were in the right order. In a third experiment, using a single-presentation lexical decision task, TL nonwords produced longer latencies than the orthographic and phonological controls, whereas there was only a small phonological effect restricted to the error data. These results suggest that TL similarity effects are orthographic--rather than phonological--in nature.     

The Hebb repetition effect as a laboratory analogue of novel word learning

The present study tests the hypothesis that a common ordering mechanism underlies both short-term serial recall of verbal materials and the acquisition of novel long-term lexical representations, using the Hebb repetition effect. In the first experiment, participants recalled visually presented nonsense syllables following a typical Hebb effect learning protocol. Replicating the Hebb repetition effect, we observed improved recall for repeated sequences of syllables. In the second experiment, the same participants performed an auditory lexical decision task, which included nonwords that were constructed from the syllables used in the first experiment. We observed inhibited rejection of nonwords that were composed of the repeated Hebb sequences, compared to nonwords that were built from nonrepeated filler sequences. This suggests that a long-term phonological lexical representation developed during Hebb learning. Accordingly, the relation between immediate serial recall and word learning is made explicit by arguing that the Hebb repetition effect is a laboratory analogue of naturalistic vocabulary acquisition.     

The Hebb repetition effect as a laboratory analogue of novel word learning

The present study tests the hypothesis that a common ordering mechanism underlies both short-term serial recall of verbal materials and the acquisition of novel long-term lexical representations, using the Hebb repetition effect. In the first experiment, participants recalled visually presented nonsense syllables following a typical Hebb effect learning protocol. Replicating the Hebb repetition effect, we observed improved recall for repeated sequences of syllables. In the second experiment, the same participants performed an auditory lexical decision task, which included nonwords that were constructed from the syllables used in the first experiment. We observed inhibited rejection of nonwords that were composed of the repeated Hebb sequences, compared to nonwords that were built from nonrepeated filler sequences. This suggests that a long-term phonological lexical representation developed during Hebb learning. Accordingly, the relation between immediate serial recall and word learning is made explicit by arguing that the Hebb repetition effect is a laboratory analogue of naturalistic vocabulary acquisition.     

Is dependence on phonological information in children's reading a product of instructional approach?

Eight-year-old British children were found to be less accurate at rejecting pseudohomophones than ordinary nonwords in a lexical decision task, but 8-year-old New Zealand children did not show this effect. A subsequent homophone decision task showed that this difference was not due to the New Zealand children being unable to distinguish pseudohomophones from other nonwords. The New Zealand children, however, were less accurate than the British children in pronouncing the pseudohomophones they had identified. It was argued that the British children tended to sound out the items before making a choice in the lexical decision task, which gave salience to phonological rather than visual information, resulting in increased errors to the pseudohomophones. It was concluded that where the British children showed this dependency on use of phonological information it was a product of the teaching approach they had experienced.     

Is there an Effect of Print Exposure on the Word Frequency Effect and the Neighborhood Size Effect?

Orthographic and phonological processing skills have been shown to vary as a function of reader skill (Stanovich & West, Reading Research Quarterly, 24, 402-433, 1989; Unsworth & Pexman, Quarterly Journal of Experimental Psychology, 56A, 63-81, 2003). One variable known to contribute to differences between readers of higher and lower skill is amount of print exposure: higher skilled readers read more often than lower skilled readers, and their increased print exposure is associated with faster responding to words and nonwords in lexical decision tasks. The present experiments examined the effect of print exposure on the word frequency effect and neighborhood size effect. We conclude that the different outcomes reported in previous studies (Chateau & Jared, Memory and Cognition, 28, 143-153, 2000; Lewellen, Goldinger, Pisoni, & Greene, Journal of Experimental Psychology: General, 122, 316-330, 1993) were due to the type of nonwords used in the lexical decision task (regular nonwords versus pseudohomophones). Our results are explained in terms of differences in the reliance on orthographic and phonological information between readers of higher and lower print exposure.     

Phonological priming in spoken word recognition: Task effects

In two experiments, we examined the role of phonological relatedness between spoken items using both the lexical decision task and the shadowing task. In Experiment 1, words were used as primes and overlaps of zero (control), one, two, or all four or five (repetition) phonemes were compared. Except for the repetition conditions, in which facilitation was found, phonological overlap resulted in interference on word responses. These effects occurred in both tasks but were larger in lexical decision than in shadowing. The effects that were evident in shadowing can be attributed to an attentional mechanism linked to the subjects' expectancies of repetitions. The extra effects obtained in lexical decision can be interpreted by taking into account both activation of the response corresponding to the prime's lexical status and postlexical processes that check for phonological congruency between prime and target. In Experiment 2, some modifications were introduced to prevent the involvement of strategic factors, and pseudowords were used as primes. No effect at all was observed in shadowing, whereas in lexical decision interference effects occurred, which is consistent with the hypothesis that lexical decision may be negatively affected by finding a phonological discrepancy at the same time as the primed response is reactivated. Neither experiment provided evidence for the occurrence of phonological priming in the perceptual processing of words.     

Automatic phonological coding of unattended printed words

A lexical decision response to an attended printed word can be slowed when the word is accompanied by an unattended word that is semantically related. Does this hold for an unattended word that is not related to the target word but sounds as if it is? The homophone WASTE can be shown to affect the lexical decision response to RUBBISH, but how does the incongruently related homophone WAIST affect RUBBISH? If incongruent homophones of words related to the attended word can influence processing when they are not being attended to, then it must be through automatic processing into a phonological code, either before or after lexical access. Experiment 1 reports such an effect, and it is concluded that a phonological representation is generated preattentively and influences the semantic processing of the attended word after generation of that representation. Experiment 2 confirms the effect and investigates the possibility that the effect exists because of the strategic use of phonological encoding of attended words. To discourage the use of a phonological strategy for lexical access, all nonwords were pseudohomophones. The influence persisted, however, with attended words still being affected by the presence of incongruent homophones of related words.     

Age of acquisition, word frequency, and the role of phonology in the lexical decision task

In five experiments, we examined the respective roles of word age of acquisition (AoA) and frequency in the lexical decision task. The two variables were manipulated orthogonally (while controlling for concreteness and length) in fully factorial designs. Experiment 1 was a conventional lexical decision task, and Experiments 2-5 involved various attempts to interfere with reliance upon phonology. In Experiment 2, only orthographically illegal nonwords were used; in Experiment 3, pseudohomophone nonwords; in Experiment 4, articulatory suppression by the recitation of a nursery rhyme; and in Experiment 5, articulatory suppression by the repetition of a single word. The same basic pattern of results was observed in all experiments: There were main effects of both AoA and frequency, which interacted in such a way that the AoA effect was larger for low- than for high-frequency words. Although the AoA effect was reduced by manipulations intended to interfere with phonological processing, the manipulations did not eliminate the effect. The results are discussed in terms of current models of reading in which it is proposed that AoA has its primary effect on the retrieval of lexical phonology, which appears to be consulted automatically in the lexical decision task.     

The Role of Antibody in Korean Word Recognition

A subsyllabic phonological unit, the antibody, has received little attention as a potential fundamental processing unit in word recognition. The psychological reality of the antibody in Korean recognition was investigated by looking at the performance of subjects presented with nonwords and words in the lexical decision task. In Experiment 1, the nonwords with a high-frequency antibody were processed more slowly than those with a low-frequency antibody. Experiment 2 showed that separating the antibody unit is advantageous in processing certain types of Korean words. These results indicate that the antibody is a part of the lexical representation system and is a fundamental unit of lexical processing.     

Reading strategies in English by adults whose first language is Spanish

The performance of nine Spanish speakers on tests of single-word reading and phonological awareness in English was examined and compared to that of monolingual adults and to that of monolingual children of similar reading ability. Even though the Spanish participants had several years experience of reading and writing in English and performed well at reading nonwords, they showed little evidence of phonological processing strategies when reading familiar words. For example, they performed relatively poorly at written rhyme judgements despite good performance on tests of phonological awareness. When compared to monolingual English children, the Spanish speakers made fewer phonological errors on tests of visual lexical decision and written homophone definition. Unlike the children, they showed no evidence of a regularity effect in reading. Only on unfamiliar words did they show evidence of phonological processing in reading. Possible explanations of this pattern of performance are discussed.     

Do transposed-letter similarity effects occur at a prelexical phonological level?

Nonwords created by transposing two letters (e.g., RELOVUTION) are very effective at activating the lexical representation of their base words (Perea & Lupker, 2004). In the present study, we examined whether the nature of transposed-letter (TL) similarity effects was purely orthographic or whether it could also have a phonological component. Specifically, we examined transposed-letter similarity effects for nonwords created by transposing two nonadjacent letters (e.g., relovución–REVOLUCIÓN) in a masked form priming experiment using the lexical decision task (Experiment 1). The controls were (a) a pseudohomophone of the transposed-letter prime (relobución–REVOLUCIÓN; note that B and V are pronounced as /b/ in Spanish) or (b) an orthographic control (relodución–REVOLUCIÓN). Results showed a similar advantage of the TL nonword condition over the phonological and the orthographic control conditions. Experiment 2 showed a masked phonological priming effect when the letter positions in the prime were in the right order. In a third experiment, using a single-presentation lexical decision task, TL nonwords produced longer latencies than the orthographic and phonological controls, whereas there was only a small phonological effect restricted to the error data. These results suggest that TL similarity effects are orthographic—rather than phonological—in nature.     

Modulation of brain activity during phonological familiarization

We measured brain activity in 12 adults for the repetition of auditorily presented words and nonwords, before and after repeated exposure to their phonological form. The nonword phoneme combinations were either of high (HF) or low (LF) phonotactic frequency. After familiarization, we observed, for both word and nonword conditions, decreased activation in the left posterior superior temporal gyrus, in the bilateral temporal pole and middle temporal gyri. At the same time, interaction analysis showed that the magnitude of decrease of activity in bilateral posterior temporal lobe was significantly smaller for LF nonwords, relative to words and HF nonwords. Decrease of activity in this area also correlated with the size of behavioral familiarization effects for LF nonwords. The results show that the posterior superior temporal gyrus plays a fundamental role during phonological learning. Its relationship to sublexical and lexical phonological processing as well as to phonological short-term memory is discussed.     

The use of phonological information by good and poor readers in memory and reading tasks

There has been a recent debate about the utilization of phonological information by poor readers in both working memory and reading tasks. The purpose of the first experiment in this study was to examine whether the absence of phonological similarity effects in working memory reported in previous studies was due to inappropriate levels of task difficulty. Poor readers and their reading age controls were found to show a normal effect when the memory task was at an appropriate level of difficulty, but no effect when a large number of items had to be recalled. However, in a recognition memory task, the poor readers chose orthographically similar pairs, whereas the reading-age and chronological age controls chose phonologically similar pairs. The purpose of a final experiment was to determine whether or not the good and poor readers could be differentiated in terms of their reading strategies; both groups showed regularity effects in a naming task and pseudohomophone effects in a lexical decision task. However, although poor readers could read three-letter nonwords as well as their controls, they were significantly impaired in reading more complex one-syllable nonwords. It was concluded that poor readers may have a phonological dysfunction in some aspects of reading that is unrelated to whether or not they show phonological similarity effects in working memory. Impaired segmentation skills may underly their difficulties in both reading and nonreading tasks.     

How brand names are special: brands,words, and hemispheres

Previous research has consistently shown differences between the processing of proper names and of common nouns, leading to the belief that proper names possess a special neuropsychological status. We investigate the category of brand names and suggest that brand names also have a special neuropsychological status, but one which is different from proper names. The findings suggest that the hemispheric lexical status of the brand names is mixed--they behave like words in some respects and like nonwords in others. Our study used familiar upper case brand names, common nouns, and two different types of nonwords ("weird" and "normal") differing in length, as stimuli in a lateralized lexical decision task (LDT). Common nouns, brand names, weird nonwords, and normal nonwords were recognized in that decreasing order of speed and accuracy. A right visual field (RVF) advantage was found for all four lexical types. Interestingly, brand names, similar to nonwords, were found to be less lateralized than common nouns, consistent with theories of category-specific lexical processing. Further, brand names were the only type of lexical items to show a capitalization effect: brand names were recognized faster when they were presented in upper case than in lower case. In addition, while string length affected the recognition of common nouns only in the left visual field (LVF) and the recognition of nonwords only in the RVF, brand names behaved like common nouns in exhibiting length effects only in the LVF.     

A transfer analysis of the repetition effect in the lexical and ambiguity decision tasks

Two experiments were performed in an attempt to evaluate explanations of repetition priming-the facilitation observed when the same word is processed a second time in the same task. One task employed was lexical decision (word/nonword) and the other was ambiguity decision (ambiguous/ unambiguous). In the first experiment, transfer on a lexical decision task was measured following either a lexical decision or an ambiguity decision. When the identical lists were processed in the first phase for lexical and ambiguity decision, equal repetition effects were obtained on lexical decision. However, when the ambiguity task was presented without nonwords, no repetition priming occurred. In a second experiment, the within-task repetition effect was large for the ambiguity decision, whereas no transfer was obtained from lexical decision to ambiguity decision. The results were interpreted as being consistent with a transfer-appropriate processing account of repetition priming.     

Lexical coherence in short-term memory: Strategic reconstruction or “semantic glue”?

This study explores the foundation of lexical/semantic phoneme binding effects in verbal short-term memory (STM). The immediate serial recall of pure lists of words and nonwords was compared with the recall of mixed lists that had either a predictable, alternating structure (e.g., wnwnwn) or an unpredictable structure (i.e., the serial positions of the words/nonwords could not be known in advance). The study provides evidence for two separate mechanisms by which long-term linguistic knowledge contributes to STM. First, there was evidence for automatic lexical/semantic binding effects that were independent of knowledge of lexical status. The nonwords in both types of mixed list damaged word recall and encouraged the phonological elements of words to migrate. In both alternating and unpredictable mixed lists, the phonemes of words were more likely than the phonemes of nonwords to be recalled together as a coherent item, suggesting that lexical/semantic knowledge encourages the phonological elements of words to emerge together in immediate serial recall, even when lexical status is unknown. Secondly, there was evidence for “strategic redintegration”, which was dependent on prior knowledge of the lexical status of the items in mixed lists. When participants recalled items that they knew to be words in advance, they were able to use this knowledge to constrain their responses so that they were more likely to be lexically appropriate. These findings motivate modifications to current theories of the interaction between linguistic knowledge and verbal short-term memory.