Activation Of Phonological Codes Research Articles

Orthographic and Phonological Code Activation in Deaf and Hearing Readers.

Grainger et al. (2006) were the first to use ERP masked priming to explore the differing contributions of phonological and orthographic representations to visual word processing. Here we adapted their paradigm to examine word processing in deaf readers. We investigated whether reading-matched deaf and hearing readers (n = 36) exhibit different ERP effects associated with the activation of orthographic and phonological codes during word processing. In a visual masked priming paradigm, participants performed a go/no-go categorization task (detect an occasional animal word). Critical target words were preceded by orthographically-related (transposed letter - TL) or phonologically-related (pseudohomophone - PH) masked non-word primes were contrasted with the same target words preceded by letter substitution (control) non-words primes. Hearing readers exhibited typical N250 and N400 priming effects (greater negativity for control compared to TL or PH primed targets), and the TL and PH priming effects did not differ. For deaf readers, the N250 PH priming effect was later (250-350 ms), and they showed a reversed N250 priming effect for TL primes in this time window. The N400 TL and PH priming effects did not differ between groups. For hearing readers, those with better phonological and spelling skills showed larger early N250 PH and TL priming effects (150-250 ms). For deaf readers, those with better phonological skills showed a larger reversed TL priming effect in the late N250 window. We speculate that phonological knowledge modulates how strongly deaf readers rely on whole-word orthographic representations and/or the mapping from sublexical to lexical representations.

Bottom-up processes dominate early word recognition in toddlers

This study set out to investigate whether the ‘phonological onset preference effect’ often reported in adult studies using the visual world task (i.e., increased attention to an object that is phonologically-related to a spoken-target word, such as boat-bear) is also contingent upon toddler participants having sufficient preview time to inspect the picture stimuli. Picture preview is thought to support the activation of phonological codes which can then be matched to the phonological representations extracted from incoming speech signals and the picture stimuli, supporting the ‘phonological mapping hypothesis’. We found that both toddlers and adults were able to show an early phonological onset preference in short preview conditions, though, adults' early phonological onset preferences in the short preview condition was extinguished by the presence of a semantic competitor, replicating previous adult findings (Huettig & McQueen, 2007). Removal of a semantic competitor reinstated the phonological onset preference effect under short preview conditions for adults. Our findings indicate that toddlers are driven more by bottom-up, phonological information when selecting a referent in a visual world task, as compared to adults who are more inclined to exploit top-down, semantic information when directing their attention to a visual object, especially when there is insufficient preview time. We propose that, when implicit naming is improbable in short-preview conditions, a phonological onset preference effect is driven by mapping on the visual-semantic levels, which is more susceptible to top-down influences.

Do Readers Integrate Phonological Codes Across Saccades? A Bayesian Meta-Analysis and a Survey of the Unpublished Literature.

It is commonly accepted that phonological codes can be activated parafoveally during reading and later used to aid foveal word recognition- a finding known as the phonological preview benefit. However, a closer look at the literature shows that this effect may be less consistent than what is sometimes believed. To determine the extent to which phonology is processed parafoveally, a Bayesian meta-analysis of 27 experiments and a survey of the unpublished literature were conducted. While the results were generally consistent with the phonological preview benefit (>90% probability of a true effect in gaze durations), the size of the effect was small. Readers of alphabetical orthographies obtained a modest benefit of only 4 ms in gaze durations. Interestingly, Chinese readers showed a larger effect (6–14 ms in size). There was no difference in the magnitude of the phonological preview benefit between homophone and pseudo-homophone previews, thus suggesting that the modest processing advantage is indeed related to the activation of phonological codes from the parafoveal word. Simulations revealed that the results are relatively robust to missing studies, although the effects may be 19–22% smaller if all missing studies found a null effect. The results suggest that while phonology can be processed parafoveally, this happens only to a limited extent. Because phonological priming effects in single-word recognition are small (10–13 ms; Rastle & Brysbaert, 2006) and there is a loss of visual acuity in the parafovea, it is argued that large phonological preview benefit effects may be unlikely.

An electrophysiological analysis of the time course of phonological and orthographic encoding in written word production

ABSTRACTRecent evidence suggests that individuals generate written words based on both spelling and sound. The present study used event-related potentials (ERPs) to examine the relative time course of orthographic and phonological activation. We adopted Chinese as a target language in which spelling and sound are largely dissociated. Native speakers of Chinese Mandarin were presented with coloured pictures and wrote down colour and picture names as adjective–noun phrases. Colour and picture names were either phonologically related, orthographically related, or unrelated. EEG revealed phonological effects in the 200–500 ms time window, starting at 206 ms after picture onset, and orthographic effects in the 300–400 ms time window, starting at 298 ms. The results of our study suggest that activation of phonological codes takes place approximately 100 ms earlier than access to orthographic codes, which provides evidence for phonological encoding as early sources of constraint in written word production.

Parafoveal Processing in Chinese Sentence Reading: Early Extraction of Radical Level Phonology.

The present study separated radical level phonology from character level phonology to explore the reliance on phonology during Chinese sentence reading with eye movement recording in a boundary paradigm. Participants viewed sentences with either regular, irregular, orthographically dissimilar homophone, or orthographically dissimilar non-homophone previews for the targets. Both regular and irregular characters contained the target character as the phonetic radical, with the regular character sharing the identical sound with its target phonetic radical. In Experiment 1, the irregular previews were different from the target phonetic radicals both in the first consonant and final compound vowels. In Experiment 2, the irregular characters would be replaced by the semi-regular previews, which shared the same final compound vowels but not the first consonant with the target characters. The radical level phonological preview benefit was obtained by the comparison between regular and irregular characters, while the character level phonological preview benefit was shown by the visually dissimilar homophones compared with the unrelated control condition. The preview benefit from parafoveal regular characters compared with irregular characters was observed in the first fixation duration, suggesting the early activation of phonological codes at radical levels. However, this preview benefit depends on phonological overlapping between the phonetic radicals and their host characters; it could be activated only when the pronunciation of the phonogram was totally consistent with that of its phonetic radical. Furthermore, the null preview effect of visually dissimilar homophones indicates no activation of phonological codes at the character level during Chinese sentence reading.

Time course analyses of orthographic and phonological priming effects in developing readers.

It has been assumed that fluent reading requires efficient integration of orthographic and phonological codes. However, it is thus far unclear how this integration process develops when children learn to become fluent readers. Therefore, we used masked priming to investigate time courses of orthographic and phonological code activation in children at incremental levels of reading development (second, fourth and sixth grade). The first study used targets with small phonological differences between phonological and orthographic primes, which are typical in transparent orthographies. The second study manipulated the strength of the phonological difference between prime and target to clarify whether phonological difference influences phonological priming effects. Results in both studies showed that orthographic priming effects became facilitative at increasingly short durations during reading development, but phonological priming was absent. These results are taken to suggest that development of reading fluency is accompanied by increased automatization of orthographic representations. The absence of phonological priming suggests that developing readers cannot yet activate phonological codes automatically.

Contrasting eye-movements in reading aloud and reading silently to localise a speech deficit.

Contrasting eye-movements in reading aloud and reading silently to localise a speech deficit.

Reading Difficulties in Adult Deaf Readers of French: Phonological Codes, Not Guilty!

Deaf people often achieve low levels of reading skills. The hypothesis that the use of phonological codes is associated with good reading skills in deaf readers is not yet fully supported in the literature. We investigated skilled and less skilled adult deaf readers' use of orthographic and phonological codes in reading. Experiment 1 used a masked priming paradigm to investigate automatic use of these codes during visual word processing. Experiment 2 used a serial recall task to determine whether orthographic and phonological codes are used to maintain words in memory. Skilled hearing, skilled deaf, and less skilled deaf readers used orthographic codes during word recognition and recall, but only skilled hearing readers relied on phonological codes during these tasks. It is important to note that skilled and less skilled deaf readers performed similarly in both tasks, indicating that reading difficulties in deaf adults may not be linked to the activation of phonological codes during reading.

Functional MRI evidence for modulation of cerebral activity by grapheme-to-phoneme conversion in French, and by the variable of gender

This fMRI study aims to assess the effect of two variables on the cerebral substrate of phonological processing during visual phoneme detection: (a) the difficulty level (type) of grapheme-to-phoneme conversion (GPC, letter-sound mapping) with two modalities, simple (S) and complex (C); and (b) the gender of participants, females (F) vs. males (M). The behavioral results have shown that simple items were processed more accurately than complex ones. At the cerebral level, phoneme detection activated the left-hemisphere phonological network and several regions of this network were modulated by the GPC type. Specifically, the activity of the superior posterior temporal gyrus was significantly higher for simple grapheme detection and suggests automatic activation of phonological representations; the activity of the inferior temporal gyrus was significantly higher for complex grapheme detection, suggesting greater demands of the integrative processes for solving competitive and inhibitory processes induced by the visual and phonological properties of stimuli. With respect to gender variable, we obtained significant interaction between GPC and gender. This effect showed higher accuracy for simple graphemes in females and suggests that female participants were more proficient than males for detecting simple items. This effect suggests easier and more rapid activation of phonological codes, probably based on a specific visual strategy, different from males. This is supported by the additional activation of the lingual gyrus in females for processing simple graphemes, although the exact explanation of this effect is not clear yet and requires supplementary experimentation and evidence. Overall, our results indicate that the cognitive mechanisms and cerebral correlates of phonological processing may depend on intrinsic and extrinsic variables, such as GPC and gender.

Automatic activation of phonology in silent reading is parallel: Evidence from beginning and skilled readers

The picture–word interference paradigm was used to shed new light on the debate concerning slow serial versus fast parallel activation of phonology in silent reading. Prereaders, beginning readers (Grades 1–4), and adults named pictures that had words printed on them. Words and pictures shared phonology either at the beginnings of words (e.g., DOLL– DOG) or at the ends of words (e.g., FOG– DOG). The results showed that phonological overlap between primes and targets facilitated picture naming. This facilitatory effect was present even in beginning readers. More important, from Grade 1 onward, end-related facilitation always was as strong as beginning-related facilitation. This result suggests that, from the beginning of reading, the implicit and automatic activation of phonological codes during silent reading is not serial but rather parallel.

The time course of orthographic and phonological code activation.

The present study used event-related potentials (ERPs) to examine the time course of orthographic and phonological priming in the masked priming paradigm. Participants monitored visual target words for occasional animal names, and ERPs to nonanimal critical items were recorded. These critical items were preceded by different types of primes: Orthographic priming was examined using transposed-letter (TL) primes (e.g., barin-BRAIN) and their controls (e.g., bosin-BRAIN); phonological priming was examined using pseudohomophone primes (e.g., brane-BRAIN) and their controls (e.g., brant-BRAIN). Both manipulations modulated the N250 ERP component, which is hypothesized to reflect sublexical processing during visual word recognition. Orthographic (TL) priming and phonological (pseudohomophone) priming were found to have distinct topographical distributions and different timing, with orthographic effects arising earlier than phonological effects.

Activation of Phonological Codes during Reading: Evidence from Errors Detection and Eye Movements

This experiment explored the role of phonology in the activation of word meanings when homophonic and nonhomophonic errors were embedded in meaningful texts. The resulting data supported the position that phonological codes are activated very early in eye fixation and are compatible with the verification model of Van Orden (1987).

Multiplication by eye and by ear for Chinese-speaking and English-speaking adults.

English-speaking (n = 32) and Chinese-speaking adults (n = 32) solved single-digit multiplication problems. In one condition, problems were presented as visual digits (e.g., 8 x 9). In the other condition, problems were presented as auditory number words in the participant's first language (e.g., /eit/ /taimz/ /nain/). Chinese-speaking adults made proportionately more operand-intrusion errors (e.g., 4 x 8 = 24) than English-speaking adults. Both groups made more operand-intrusion errors with auditory than with visual presentation. These findings are similar to those found when participants solve problems presented as visual number words (e.g., eight x nine), suggesting that in both cases the activation of phonological codes interferes with processing.

Spelling-sound regularity effects on eye fixations in reading.

An interaction of word frequency and word regularity has typically been observed in naming and lexical decision experiments in which, in addition to an overall effect of word frequency, responses to low-frequency exception words are slower than those to low-frequency regular words, while no such difference occurs with high-frequency words. The only eye movement study to examine this effect in reading (Inhoff & Topolski, 1994) reported only transient effects of regularity. In the present experiment, we examined the frequency x regularity interaction using different stimuli than those of Inhoff and Topolski and also varied the parafoveal preview of the target word prior to fixation. When the preview was valid, the frequency x regularity interaction appeared. However, with an invalid preview, the effect of regularity disappeared. The results suggest that the activation of phonological codes is a very early component of reading.

Activation of phonological codes during eye fixations in reading.

Activation of phonological codes during eye fixations in reading.

Activation of phonological codes during eye fixations in reading.

Two experiments addressed the issue of whether phonological codes are activated early in a fixation during reading using the fast-priming technique (S. C. Sereno & K. Rayner, 1992). Participants read sentences and, at the beginning of the initial fixation in a target location, a priming letter string was displayed, followed by the target word. Phonological priming was assessed by the difference in the gaze duration on the target word between when the prime was a homophone and when it was a control word equated with the homophone on orthographic similarity to the target. Both experiments demonstrated homophonic priming with prime durations of about 35 ms, but only for high-frequency word primes, indicating that lexicality was guiding the speed of the extraction of phonological codes early in a fixation. Evidence was also obtained for orthographic priming, and the data suggest that orthographic and phonological priming effects interact in a mutually facilitating manner.

Activation of phonological codes before access to character meaning in written Chinese.

Activation of phonological codes before access to character meaning in written Chinese.

Activation of phonological codes before access to character meaning in written Chinese.

Activation of phonological codes before access to character meaning in written Chinese.

Brain potentials and the availability of semantic and phonological codes over time.

ERPs were recorded from subjects performing semantic and rhyme matching tasks using either spoken words, printed words or pictures as stimuli. Mismatches enhanced N400 (in the semantic task) and N450 (in the rhyme task). Onset and peak latencies were shorter for N450 than for N400 with spoken words; this relationship was inverted for pictures. Thus these latencies could index availability of semantic and phonological codes. For printed words, the latencies were shorter for N400 than N450, a result that supports direct-access modes of reading with late phonological code activation. The longer latencies found for N400 and N450 to pictures could suggest longer initial decoding for pictures with respect to words.

The time course of orthographic and phonological code activation in the early phases of visual word recognition

In a recent article, Ferrand and Grainger (1992) reported that briefly presented, forward-masked, nonword primes that share letters with a target word facilitate lexical decision performance at prime exposures of 33 msec, but no longer affect performance at 67-msec exposures. In the same experiment, nonword primes that were homophonic with targets did not affect performance relative to orthographic controls at 33-msec prime exposures, but produced facilitatory priming effects at prime exposures of 67 msec. In the present study, we extend these results, varying prime exposures from 17 msec to 100 msec. Orthographic facilitation was found with prime exposures from 17 msec to 50 msec, whereas phonological facilitation only started to emerge at exposures of 50 msec. The results demonstrate a distinct time course for the buildup of orthographic and phonological information during the processing of pronounceable strings of letters.