Phonological coding in good and poor readers

EXPRESS: When words collide: Bayesian meta-analyses of distractor and target properties in the picture-word interference paradigm

In the picture-word interference paradigm, participants name pictures while ignoring a written or spoken distractor word. Naming times to the pictures are slowed down by the presence of the distractor word. The present study investigates in detail the impact of distractor and target word properties on picture naming times, building on the seminal study by Miozzo and Caramazza (2003) "When more is less: A counterintuitive effect of distractor frequency in the picture-word interference paradigm. Journal of Experimental Psychology. General." We report the results of several Bayesian meta-analyses, based on 26 datasets. These analyses provide estimates of effect sizes and their precision for several variables and their interactions. They show the reliability of the distractor frequency effect on picture naming latencies (latencies decrease as the frequency of the distractor increases) and demonstrate for the first time the impact of distractor length, with longer naming latencies for trials with longer distractors. Moreover, distractor frequency interacts with target word frequency to predict picture naming latencies. The methodological and theoretical implications of these findings are discussed.

Morphological facilitation and semantic interference in compound production: An ERP study

This study investigates the production of nominal compounds (Experiment 1) and simple nouns (Experiment 2) in a picture-word interference (PWI) paradigm to test models of morpho-lexical representation and processing. The continuous electroencephalogram (EEG) was registered and event-related brain potentials [ERPs] were analyzed in addition to picture-naming latencies. Experiment 1 used morphologically and semantically related distractor words to tap into different pre-articulatory planning stages during compound production. Relative to unrelated distractors, naming was speeded when distractors corresponded to morphemes of the compound (sun or flower for the target sunflower), but slowed when distractors were from the same semantic category as the compound (tulip ➔ sunflower). Distractors from the same category as the compound's first constituent (moon ➔ sunflower) had no influence. The diverging effects for semantic and morphological distractors replicate results from earlier studies. ERPs revealed different effects of morphological and semantic distractors with an interesting time course: morphological effects had an earlier onset. Comparable to the naming latencies, no ERP effects were obtained for distractors from the same semantic category as the compound's first constituent. Experiment 2 investigated the effectiveness of the latter distractors, presenting them with pictures of the compounds' first constituents (e.g., moon ➔ sun). Interference was confirmed both behaviorally and in the ERPs, showing that the absence of an effect in Experiment 1 was not due to the materials used. Considering current models of speech production, the data are best explained by a cascading flow of activation throughout semantic, lexical and morpho-phonological steps of speech planning.

Electrophysiological characterization of facilitation and interference in the picture-word interference paradigm

The picture-word interference paradigm is often used to investigate the processes underlying word production. In this paradigm, participants name pictures while ignoring distractor words. The aim of this study is to investigate the processes underlying this task and how/when they differ from those involved in simple picture naming. It examines the electrophysiological signature of general interference (longer response times with than without distractors) and facilitation (shorter response times for distractor-word stimuli overlapping in phonemes/orthography) effects. Mass univariate analyses are used to determine the temporal boundaries and spatial distribution of these effects without a priori restrictions in the time/space dimensions. Topographic pattern analyses complement this information by indicating whether (and when) the neural networks differ across conditions. Results suggest that the general interference effect has two loci, the grammatical encoding and the phonological encoding of the target word, with different neural networks involved in the two tasks during part of the grammatical encoding process. Furthermore, the electrophysiological signature of interference and facilitation effects in the time window of phonological encoding is highly similar, suggesting that the two effects could result from the same underlying mechanism. These findings are discussed in the light of existing accounts of interference and facilitation effects.

Are there independent lexical and nonlexical routes in word processing? An evaluation of the dual-route theory of reading

One of the most popular and influential theories of word processing, dual-route theory, proposes that there are two functionally independent means of processing words, one involving access to lexical knowledge and the other involving nonlexical grapheme-to-phoneme conversion. Three topics germane to this theory are the processing of nonwords, spelling regularity effects, and the manner in which reading may be impaired following selective damage to either route. This paper evaluates evidence on these topics, and in each case the claims of the theory for an independent nonlexical processing route are called into question. This conclusion is further supported by a discussion of the linguistic constraints that limit any nonlexical grapheme—phoneme conversion process. Some alternative approaches to visual word processing, which share the assumption that lexical knowledge can guide the assembly of phonological information, are discussed. It is argued that these approaches should direct future research.

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.

Investigating the interplay between semantic and phonological distractor effects in picture naming

In this paper, we investigate the interplay between phonological facilitation and semantic interference effects in picture naming. We use a double distractor variant of the classic picture-word interference paradigm to investigate whether the reported interaction between these effects is dependent on the two types of related information being presented by the same distractor word or not. While prior studies using single mixed distractors such as pigeon for the target PIG have reported an interaction between phonological facilitation and semantic interference, we find additivity when the two types of related information come from two different distractor words. Possible implications of this result for how activation is transmitted within the speech production system are discussed.

The production of determiners: evidence from French

In numerous languages determiner forms depend not only on semantic information but also on several other kinds of information, such as the grammatical gender of the controlling noun or the phonological properties of the context. In the present research we contrasted two possible accounts of determiner retrieval: one in which every type of required information is bundled into a unitized representation for determiner retrieval and one in which each type of information can individually activate determiner forms. These alternative hypotheses were investigated in three experiments in which native speakers of French named pictures with simple [determiner + noun] or complex [determiner + adjective + noun] noun phrases. In the experiments, the properties of the contextual cues that drive the retrieval of the determiner were manipulated - for example, we manipulated the number of determiner forms that are compatible with a given grammatical gender and the number of grammatical genders that a given determiner form can be used with. Neither hypothesis can fully account for the results of the three experiments. However, a hybrid hypothesis that combines the principal features of the two hypotheses provides a good account of the data.

Automaticity training for dyslexics: An experimental study

Less-skilled readers may experience a processing bottleneck in reading comprehension produced by a failure to automate word recognition. The automaticity hypothesis predicts that training which increases rapid and automatic word recognition will improve comprehension. To date few studies have tested this hypothesis. Our goal was to test the automaticity hypothesis by training dyslexic readers (n=35) to access the meaning of words more rapidly. Training consisted of speeded word games implemented on a microcomputer that provided feedback concerning subjects' speed and accuracy using sound and graphics. Three experimental tasks were administered both before and after training in which trials with trained and untrained stimuli were randomly intermixed. The measures were latency and accuracy of word vocalization, sentence comprehension, and a dual-task procedure designed to measure automaticity. Although pre/post improvement was larger for trained than untrained stimuli, reaction time on the word vocalization and sentence comprehension tasks improved significantly for both trained and untrained stimuli. In contrast, automaticity and sentence comprehension accuracy improved significantly for trained but not untrained stimuli. The training effect in comprehension remained when controlling for increases in word knowledge. The results support the automaticity hypothesis and further suggest that severely disabled readers may benefit from training in automatic word recognition.

Mechanisms of attention: a developmental study

A model of selective attention is proposed which contains a number of properties. First, stimuli which are irrelevant to the subjects' task can be analyzed to semantic levels automatically, and such stimuli can produce intrusion/interference effects. Second, two mechanisms by which selection is achieved are habituation to, and inhibition of, these irrelevant stimuli. A series of studies demonstrates that both the ability to process automatically irrelevant stimuli and the habituation mechanisms of attention are observable by Grade 2, whereas the inhibitory mechanism is not always evident at this stage. It is suggested that the greater distractability of children in certain situations may be due in part to the underutilization of this inhibitory mechanism. We further propose that children may be able to employ inhibitory mechanisms in more familiar perceptual-motor tasks.

Explaining the variance in reading ability in terms of psychological processes: What have we learned?

After years of confusion, the literature on individual differences in reading ability is finally beginning to coalesce around a small set of general conclusions that are endorsed by the vast majority of researchers. The most fundamental is that word decoding ability accounts for a very large proportion of the variance in reading ability at all levels. Variation in word decoding skill is primarily the result of differences in phonological abilities, rather than visual processes. Less-skilled readers are not characterized by a general inability to use context to facilitate word recognition. However, situations where such readers fail to utilize context to facilitate word recognition will arise when their slow and inaccurate decoding of words renders the context useless. Less-skilled readers display performance deficits on a wide variety of short-term memory tasks, probably due to an inability to efficiently employ various memory strategies, and most certainly due to inadequate phonological coding. Less-skilled readers may have comprehension deficits that are partially independent of word decoding skill. These problems probably arise because syntactic abilities and metacognitive strategies are inadequately developed.