Unimpaired short-term memory and rhyme judgement in congenitally speechless individuals: Implications for the notion of “articulatory coding”

In normal adults, concurrent articulation impairs short-term memory, abolishing both the phonological similarity effect and the word length effect when visual presentation is used. It also interferes with ability to judge whether visually presented words rhyme. It is generally assumed that concurrent articulation impairs performance because it prevents people from recoding material into an articulatory form. If this is the explanation, then individuals who are congenitally speechless (anarthric) or speech-impaired (dysarthric) should show the same impairments as normal individuals who are concurrently articulating—i.e. they should have reduced memory spans, fail to show word length and phonological similarity effects in short-term memory, and find rhyme judgement difficult. These predictions were tested in a study of 48 cerebral palsied individuals: 12 anarthric, 12 dysarthric, and 24 controls individually matched to the speech-impaired subjects. There was no impairment of memory span in speech-impaired subjects, who showed normal phonological similarity and word-length effects in short-term memory. Speech-impaired subjects did not differ from their controls in ability to tell whether names of pairs of pictures rhymed. These results challenge the notion that “articulatory coding” is implicated in short-term memory and rhyme judgement and suggests that processes such as rehearsal and phonemic segmentation involve generation of a more abstract central phonological code.     

Deafness, spelling and rhyme: How spelling supports written word and picture rhyming skills in deaf subjects

Orally trained, congenitally deaf adolescents and hearing, reading-age-matched control subjects made rhyme judgements for pictures and for written words. Hearing children performed the task accurately. By contrast, the deaf group were very poor at rhyme judgement for words and for pictures. For hearing children, word rhyme judgement was more accurate when the words were congruent in their spelling pattern (e.g. bat/hat), less accurate when the spelling pattern of the rhyming words was incongruent (hair/bear). Deaf subjects showed an even more pronounced effect of spelling congruence; their ability to match for rhyme when written words did not share the same spelling pattern was extremely poor. Moreover, spelling congruence predicted deaf subjects' picture rhyming skills.

We conclude that oral training for deaf people does not always permit them to achieve a reliable phonological representation of speech from lip-reading and residual hearing alone. Instead they use the written spelling of the word. This result is not predicted from some previous results that suggest that orally trained deaf people can make direct, spontaneous use of rhyme in the processing of visually presented material.     

Reading for meaning: The effects of concurrent articulation

Six experiments are reported which examine the assertion that phonological recoding for the purpose of lexical access in visual word recognition is prevented or impaired by concurrent articulation (“articulatory suppression”). The first section of this paper selectively reviews the literature, and reports two experiments which fail to replicate previous work.

The third experiment contrasts performance with visually presented words and with non-words. Latency measures show an effect of suppression that is specific to words, whilst error rates show an effect common to both words and non-words. The fourth experiment shows that if the task is changed from a judgement of rhyme (BLAME-FLAME) to one of homophony (AIL-ALE), the suppression effect seen in the latency data is eliminated, whilst error effects remain. It is suggested that, in addition to producing error effects that are not easily interpretable, suppression prevents or impairs a phonological segmentation process operating subsequent to the retrieval of whole word phonology (a process that is needed for rhyme judgement but not for one of homophony).

Experiment V shows that while suppression has no effect on the time taken to decide if printed non-words sound like real words (e.g. PALLIS), error rates increase. Experiment VI shows that suppression has no effect on either RT or errors in the same task if subjects suppress at a slower rate than in Experiment V.

It is suggested that there are at least two different phonological codes. Buffer storage and/or maintenance of phonologically coded information derived from print is affected by suppression; phonological recoding from print for the purpose of lexical access can be carried out without any interference from suppression.     

Articulatory coding and phonological judgements on written words and pictures: The role of the phonological output buffer

Abstract

The ability of Italian subjects to make phonological judgements was investigated in three experiments. The judgements comprised initial sound similarity and stress assignment on pain of both written words and pictures. Stress assignment on both words and pictures as well as initial sound similarity on pictures required the activation of phonological lexical representations, but this was not necessarily the case for initial sound similarity judgements on word pairs. The first study assessed the effects of concurrent articulatory suppression on the judgements. Experiment 2 used a concomitant task (chewing), which shares with suppression the use of articulatory components but does not involve speech programming and production. The third experiment investigated the effects of unattended speech on the phonological judgements. The results of these three experiments showed that articulatory suppression had a significant disrupting effect on accuracy in all four conditions, while neither articulatory non-speech (chewing) or unattended auditory speech had any effect on the subjects' performance. The results suggest that these phonological judgements involve the operation of an articulatory speech output component, which is not implemented peripherally and does not require the involvement of a non-articulatory input system.     

Phonological coding in rhyming and homophony judgement

Recent data concerning the effects of articulatory suppression on the time taken to decide whether pairs of letter strings rhyme or sound the same are inconsistent. A consideration of the nature of the two tasks, as well as independent experimental evidence, suggests that they have different processing requirements. Two experiments are reported. Experiment 1 shows that articulatory suppression increases rhyming judgement time for both words and non-words. Experiment 2 shows that suppression does not increase homophony judgement time for either words or non-words. It is suggested that only rhyming judgements require the registration of a post-lexical representation in the articulatory loop component of working memory. This process of registration is hindered when subvocalization is prevented by articulatory suppression.     

Difficulties in auditory organization as a cause of reading backwardness? An auditory neuroscience perspective

Over 30 years ago, it was suggested that difficulties in the ‘auditory organization’ of word forms in the mental lexicon might cause reading difficulties. It was proposed that children used parameters such as rhyme and alliteration to organize word forms in the mental lexicon by acoustic similarity, and that such organization was impaired in developmental dyslexia. This literature was based on an ‘oddity’ measure of children's sensitivity to rhyme (e.g. wood, book, good) and alliteration (e.g. sun, sock, rag). The ‘oddity’ task revealed that children with dyslexia were significantly poorer at identifying the ‘odd word out’ than younger children without reading difficulties. Here we apply a novel modelling approach drawn from auditory neuroscience to study the possible sensory basis of the auditory organization of rhyming and non‐rhyming words by children. We utilize a novel Spectral‐Amplitude Modulation Phase Hierarchy (S‐AMPH) approach to analysing the spectro‐temporal structure of rhyming and non‐rhyming words, aiming to illuminate the potential acoustic cues used by children as a basis for phonological organization. The S‐AMPH model assumes that speech encoding depends on neuronal oscillatory entrainment to the amplitude modulation (AM) hierarchy in speech. Our results suggest that phonological similarity between rhyming words in the oddity task depends crucially on slow (delta band) modulations in the speech envelope. Contrary to linguistic assumptions, therefore, auditory organization by children may not depend on phonemic information for this task. Linguistically, it is assumed that ‘book’ does not rhyme with ‘wood’ and ‘good’ because the final phoneme differs. However, our auditory analysis suggests that the acoustic cues to this phonological dissimilarity depend primarily on the slower amplitude modulations in the speech envelope, thought to carry prosodic information. Therefore, the oddity task may help in detecting reading difficulties because phonological similarity judgements about rhyme reflect sensitivity to slow amplitude modulation patterns. Slower amplitude modulations are known to be detected less efficiently by children with dyslexia.     

Phonological recoding under articulatory suppression

We report data from an experiment in which participants performed immediate serial recall of visually presented words with or without articulatory suppression, while also performing homophone or rhyme detection. The separation between homophonous or rhyming pairs in the list was varied. According to the working memory model (Baddeley, 1986; Baddeley & Hitch, 1974), suppression should prevent articulatory recoding. Nevertheless, rhyme and homophone detection was well above chance. However, with suppression, participants showed a greater tendency to false-alarm to orthographically related foils (e.g., GIVE–FIVE). This pattern is similar to that observed in short-term memory patients.     

Impairment of rhyme judgments by silent and overt articulatory suppression

Two experiments showed that articulating “blah” repeatedly aloud or silently interfered with the speed and accuracy of judging whether pairs of words rhymed. Articulation from another voice affected only accuracy, and foot tapping had no effect. This suggests that it is mainly the articulatory component of articulatory suppression that interferes with this task and that rhyme judgments of words depend on an articulatory code or an acoustic code accessed via articulation.

A third experiment confirmed these effects on speed of judgment, but there were no significant effects on errors in this experiment. Non-verbal use of the articulatory musculature in chewing also slowed performance. Similar results were obtained for word and non-word rhyme judgments, though the latter effects were somewhat weaker. It is argued that the results fail to support the theory that there are different methods of accessing phonology for words or non-words and indicate that access to phonology was via articulation, rather than a means to achieving articulation. If the task incorporated mechanisms employed in normal reading, the results refute suggestions that conversion of print to sound, whether for words or non-words, occurs prior to retrieval of an articulatory code.     

Orthography, phonology, short-term memory and the effects of concurrent articulation on rhyme and homophony judgements

The role of phonological short-term memory (pSTM) in phonological judgement tasks of print has been widely explored using concurrent articulation (CA). A number of studies have examined the effects of CA on written word/nonword rhyme and homophone judgements but the findings have been mixed and few studies have examined both tasks within subjects. Also important is the influence of orthographic similarity on such tasks (i.e., items that share phonology often strongly overlap on orthography). Although there are reports of orthographic similarity effects (e.g., LOAD-TOAD vs. DIAL-MILE) on rhyme judgements, it is unknown whether (a) similar orthographic effects are present with homophone judgements, (b) the degree to which such orthographic effects interact with CA, and (c) the degree to which such orthographic effects interact with lexical status (words vs. nonwords). The present work re-examines these three issues in a within subject design. CA and orthographic similarity yielded subtle differences across tasks. CA impaired accuracy for both homophone and rhyme judgement, but only slowed RTs on the rhyme judgement task, and then only for words. Orthographic similarity yielded an increase in false positives for similar items and vice versa for dissimilar items, suggesting a general impact of an orthographically based ‘bias’ in choosing similar or dissimilar sounding items. This pattern was amplified under CA but only on the homophone judgement task. These results highlight important interactions between phonological and orthographic representations in phonological judgement tasks, and the findings are considered both with reference to earlier studies and several models of pSTM.     

Phonological Similarity and Trace Degradation in the Serial Recall Task: When CAT helps RAT,but not MAN

Phonological similarity is observed to affect serial recall detrimentally when correct-in-position scoring is used. Two experiments investigated the role of item and position accuracy scoring of rhyming, similar nonrhyming, and dissimilar lists under immediate recall conditions; articulatory suppression; or a filled delay. In general, rhyme lists produced the best item recall but position accuracy was highest for dissimilar lists. The results are due to a category cueing effect improving item recall for rhyme lists in conjunction with a detrimental effect of phonological similarity on position accuracy.     

Hemispheric differences for orthographic and phonological processing

The role of hemispheric differences for the encoding of words was assessed by requiring subjects to match tachistoscopically presented word pairs on the basis of their rhyming or visual similarity. The interference between a word pair's orthography and phonology produced matching errors which were differentially affected by the visual field/hemisphere of projection and sex of subject. In general, right visual field/left hemisphere presentations yielded fewer errors when word pairs shared similar phonology under rhyme matching and similar orthography under visual matching. Left visual field/right hemisphere presentations yielded fewer errors when word pairs were phonologically dissimilar under rhyme matching and orthographically dissimilar under visual matching. Males made more errors and demonstrated substantially stronger hemispheric effects than females. These patterns suggested visual field/hemispheric differences for orthographic and phonological encoding occurred during the initial stages of word processing and were more pronounced for male compared to female subjects.     

The nature of rhyme processing in preliterate children

Background. Rhyme awareness is one of the earliest forms of phonological awareness to develop and is assessed in many developmental studies by means of a simple rhyme task. The influence of more demanding experimental paradigms on rhyme judgment performance is often neglected. Addressing this issue may also shed light on whether rhyme processing is more global or analytical in nature. Aims. The aim of the present study was to examine whether lexical status and global similarity relations influenced rhyme judgments in kindergarten children and if so, if there is an interaction between these two factors. Sample. Participants were 41 monolingual Dutch-speaking preliterate kindergartners (average age 6.0 years) who had not yet received any formal reading education. Method. To examine the effects of lexical status and phonological similarity processing, the kindergartners were asked to make rhyme judgements on (pseudo) word targets that rhymed, phonologically overlapped or were unrelated to (pseudo) word primes. Results. Both a lexicality effect (pseudo-words were more difficult than words) and a global similarity effect (globally similar non-rhyming items were more difficult to reject than unrelated items) were observed. In addition, whereas in words the global similarity effect was only present in accuracy outcomes, in pseudo-words it was also observed in the response latencies. Furthermore, a large global similarity effect in pseudo-words correlated with a low score on short-term memory skills and grapheme knowledge. Conclusions. Increasing task demands led to a more detailed assessment of rhyme processing skills. Current assessment paradigms should therefore be extended with more demanding conditions. In light of the views on rhyme processing, we propose that a combination of global and analytical strategies is used to make a correct rhyme judgment.     

Articulatory suppression and phonological codes in reading for meaning

The aim of this study was to investigate whether the phonological code that causes errors in printed sentence comprehension is affected by concurrent articulation. Forty adult subjects made speeded judgements of the acceptability of printed sentences. The critical sentences were foils that were (1) orthographi-cally unacceptable but phonologically acceptable (e.g. The palace had a thrown room), and (2) spelling controls that were orthographically and phonologically unacceptable (The palace had a thorns room). Half the subjects performed this task in silence (without concurrently articulating) and showed a marked phonological effect such that false alarms to phonologically acceptable foils were more frequent than false alarms to their spelling controls. The remaining subjects who performed this task with concurrent articulatory suppression showed an increase in false alarm rates, but no effect of phonology. In a control experiment using the same subjects, memory span for visually presented long and short words was measured under conditions of silence or concurrent articulation. The word length effect (Baddeley, Thomson, & Buchanan, 1975) disappeared under suppression, indicating that the suppression manipulation was highly effective. Thus the phonological codes that are used both in sentence comprehension and memory span are highly susceptible to articulatory suppression. We discuss possible relationships between phonological codes that mediate lexical access and those that support short-term verbal memory.     

Phonological encoding and ideographic reading by the disconnected right hemisphere: Two case studies

The mute disconnected right hemispheres (RHs) of two commissurotomy patients are able to understand spoken words and read printed words by matching them with pictures of the objects named. In this paper we report the results of five experiments. The RH of one patient could “evoke the sound image” of a word to the extent of matching two pictures with homonymous names (experiment 1) or with rhyming names (experiment 2) without being able to name either one. This transformation of picture to covert sound does not depend on orthographic similarity of word ends as a clue to homonymy or rhyme, nor does it improve with short-term learning. Yet neither RH can translate print into sound by matching a spelled word with a picture that has a rhyming name (experiment 3) or by matching two orthographically dissimilar rhymes, be they meaningful (experiment 4) or nonsense words (experiment 5). We suggest that these RHs read “ideographically,” recognizing words directly as visual gestalts without intermediate phonetic recoding or grapheme-to-phoneme translation.     

The homophone effect in semantic access tasks using kanji words: its relation to the articulatory suppression effect

The present study examined whether articulatory suppression influences homophone effects in semantic access tasks using Japanese kanji words. In Experiment 1, participants were required to decide whether visually presented word pairs were synonyms. This experiment replicated the homophone effect observed in previous research that showed more false positive errors in response to nonsynonym homophone pairs than to controls. The present study found that this homophone effect was also obtained under an articulatory suppression condition. In Experiment 2, participants performed a semantic decision task, in which they had to judge whether a visually presented target word was an exemplar of a definition that was shown immediately before presentation of the target word. The homophone effect observed in previous studies was replicated--that is, longer response times and more false positive errors were associated with homophones of correct exemplars than with nonhomophone control words. This homophone effect was also obtained under an articulatory suppression conditions. These results suggest that the phonological processing that produces the homophone effects in semantic access tasks using Japanese kanji words does not include articulatory mechanisms.     

The homophone effect in semantic access tasks using kanji words: Its relation to the articulatory suppression effect

The present study examined whether articulatory suppression influences homophone effects in semantic access tasks using Japanese kanji words. In Experiment 1, participants were required to decide whether visually presented word pairs were synonyms. This experiment replicated the homophone effect observed in previous research that showed more false positive errors in response to nonsynonym homophone pairs than to controls. The present study found that this homophone effect was also obtained under an articulatory suppression condition. In Experiment 2, participants performed a semantic decision task, in which they had to judge whether a visually presented target word was an exemplar of a definition that was shown immediately before presentation of the target word. The homophone effect observed in previous studies was replicated—that is, longer response times and more false positive errors were associated with homophones of correct exemplars than with nonhomophone control words. This homophone effect was also obtained under an articulatory suppression conditions. These results suggest that the phonological processing that produces the homophone effects in semantic access tasks using Japanese kanji words does not include articulatory mechanisms.     

Newly learned spoken words show long-term lexical competition effects

Newly learned spoken words (e.g., “cathedruke”) become fully engaged in the mental lexicon, as measured via lexical competition with their pre-existing phonological neighbours (e.g., “cathedral”), over the course of several hours or days, and this lexical restructuring is associated with sleep (Dumay & Gaskell, 2007). Here, we investigated the longer-term effects of word learning for three sets of novel words learned at different times using phoneme monitoring and repetition tasks. The effects of these exposure sessions on lexical memory were assessed in a battery of tests. Lexical decision latencies to pre-existing neighbouring words showed that lexical competition effects for the novel words remained observable 8 months after initial exposure. Furthermore, the order-of-acquisition of the novel words affected their production speed (but not recognition speed), with an advantage for earlier acquired words. The results suggest that the consolidation of novel words results in a long-term and stable change in the lexical competition process.     

Event-related potentials and the interaction between orthographic and phonological information in a rhyme-judgment task

Event-related potentials (ERPs) were recorded from one midline and three pairs of lateral electrodes in three experiments involving a rhyme-judgment task. Experiment 1 employed sequentially presented word pairs consisting of orthographically similar and dissimilar rhyming and nonrhyming items (RUNG-SUNG, MAKE-ACHE, BEAD-DEAD, GIFT-ROAD). Comparison of the ERPs elicited by the dissimilar pairs revealed a rhyme/nonrhyme difference in the form of an increase in the amplitude of a late negative component (N450) for nonrhyming pairs; this effect was confined almost entirely to right-hemisphere electrodes. By contrast, rhyme/nonrhyme differences in the ERPs to orthographically similar word pairs were smaller in magnitude, later in onset, and bilaterally distributed. Experiment 2 showed that this pattern of ERP effects with orthographically similar items depended upon orthographic and not visual similarity. Experiment 3 tested the hypothesis that the lack of a right-hemisphere based N450 effect with orthographically similar items resulted from the operation of an orthographic priming mechanism. ERPs to nonrhyming pairs containing a word with an inconsistent segment (COAST-FROST) were compared with visually matched controls (SPARSE-CREASE). The rhyme/nonrhyme differences in the N450 components from these two conditions were indistinguishable, although subjects found it as difficult to make nonrhyme responses to "COAST-FROST" pairs as to the orthographically similar nonrhyming items in Experiment 1. It was concluded that while "orthographic priming" accounted for the behavioral data from these experiments, it could not explain the interaction between phonology and orthography observed in the concurrently recorded ERP data.     

Cleaving automatic processes from strategic biases in phonological priming

In a phonological priming experiment using spoken Dutch words, Dutch listeners were taught varying expectancies and relatedness relations about the phonological form of target words, given particular primes. They learned to expect that, after a particular prime, if the target was a word, it would be from a specific phonological category. The expectancy either involved phonological overlap (e.g., honk-vonk, "base-spark"; expected related) or did not (e.g., nest-galm, "nest-boom"; expected unrelated, where the learned expectation after hearing nest was a word rhyming in -alm). Targets were occasionally inconsistent with expectations. In these inconsistent expectancy trials, targets were either unrelated (e.g., honk-mest, "base-manure"; unexpected unrelated), where the listener was expecting a related target, or related (e.g., nest-pest, "nest-plague"; unexpected related), where the listener was expecting an unrelated target. Participant expectations and phonological relatedness were thus manipulated factorially for three types of phonological overlap (rhyme, one onset phoneme, and three onset phonemes) at three interstimulus intervals (ISIs; 50, 500, and 2,000 msec). Lexical decisions to targets revealed evidence of expectancy-based strategies for all three types of overlap (e.g., faster responses to expected than to unexpected targets, irrespective of phonological relatedness) and evidence of automatic phonological processes, but only for the rhyme and three-phoneme onset overlap conditions and, most strongly, at the shortest ISI (e.g., faster responses to related than to unrelated targets, irrespective of expectations). Although phonological priming thus has both automatic and strategic components, it is possible to cleave them apart.     

Do speakers have access to a mental syllabary?

The first, theoretical part of this paper sketches a framework for phonological encoding in which the speaker successively generates phonological syllables in connected speech. The final stage of this process, phonetic encoding, consists of accessing articulatory gestural scores for each of these syllables in a “mental syllabary”. The second, experimental part studies various predictions derived from this theory. The main finding is a syllable frequency effect: words ending in a high-frequent syllable are named faster than words ending in a low-frequent syllable. As predicted, this syllable frequency effect is independent of and additive to the effect of word frequency on naming latency. The effect, moreover, is not due to the complexity of the word-final syllable. In the General Discussion, the syllabary model is further elaborated with respect to phonological underspecification and activation spreading. Alternative accounts of the empirical findings in terms of core syllables and demisyllables are considered.