How strongly do word reading times and lexical decision times correlate? Combining data from eye movement corpora and megastudies

We assess the amount of shared variance between three measures of visual word recognition latencies: eye movement latencies, lexical decision times and naming times. After partialling out the effects of word frequency and word length, two well-documented predictors of word recognition latencies, we see that 7-44% of the variance is uniquely shared between lexical decision times and naming times, depending on the frequency range of the words used. A similar analysis of eye movement latencies shows that the percentage of variance they uniquely share either with lexical decision times or with naming times is much lower. It is 5 – 17% for gaze durations and lexical decision times in studies with target words presented in neutral sentences, but drops to .2% for corpus studies in which eye movements to all words are analysed. Correlations between gaze durations and naming latencies are lower still. These findings suggest that processing times in isolated word processing and continuous text reading are affected by specific task demands and presentation format, and that lexical decision times and naming times are not very informative in predicting eye movement latencies in text reading once the effect of word frequency and word length are taken into account. The difference between controlled experiments and natural reading suggests that reading strategies and stimulus materials may determine the degree to which the immediacy-of-processing assumption and the eye-mind assumption apply. Fixation times are more likely to exclusively reflect the lexical processing of the currently fixated word in controlled studies with unpredictable target words rather than in natural reading of sentences or texts

Dynamic semantic cognition : Characterising coherent and controlled conceptual retrieval through time using magnetoencephalography and chronometric transcranial magnetic stimulation

Distinct neural processes are thought to support the retrieval of semantic information that is (i) coherent with strongly-encoded aspects of knowledge, and (ii) non-dominant yet relevant for the current task or context. While the brain regions that support readily coherent and more controlled patterns of semantic retrieval are relatively well-characterised, the temporal dynamics of these processes are not well-understood. This study used magnetoencephalography (MEG) and dual-pulse chronometric transcranial magnetic stimulation (cTMS) in two separate experiments to examine temporal dynamics during the retrieval of strong and weak associations. MEG results revealed a dissociation within left temporal cortex: anterior temporal lobe (ATL) showed greater oscillatory response for strong than weak associations, while posterior middle temporal gyrus (pMTG) showed the reverse pattern. Left inferior frontal gyrus (IFG), a site associated with semantic control and retrieval, showed both patterns at different time points. In the cTMS experiment, stimulation of ATL at ∼150 msec disrupted the efficient retrieval of strong associations, indicating a necessary role for ATL in coherent conceptual activations. Stimulation of pMTG at the onset of the second word disrupted the retrieval of weak associations, suggesting this site may maintain information about semantic context from the first word, allowing efficient engagement of semantic control. Together these studies provide converging evidence for a functional dissociation within the temporal lobe, across both tasks and time

The Cognitive Chronometric Architecture of Word and Picture Naming: Evidence from Onset Response and Duration

Reading is a fundamental skill for functioning in today’s society. Given the breadth of activities that require reading, it is important to develop a comprehensive model of basic reading processes. Furthermore, considering that many pictures co-appear with words in everyday life, it is imperative to understand the nature of picture identification processes, as well as how they interact with reading processes. As such, the present thesis focuses on developing a model of reading and extending it to include picture processing. In the present research, experiments on word identification (Experiments 1 and 2) examined onset reaction time (RT) in a word naming task using an additive factors method. The pattern of additive and overadditive joint effects on naming RT among Instructions (INST: name all, name words), Word Frequency (WF: log10HAL), Semantic Neighbourhood Density (SND: Inverse Ncount), and Word Type (WT: regular, exception) supported a cognitive chronometric architecture consisting of at least two cascaded stages of processing, with the orthographic lexical system as the locus of the INST x WF and the INST x SND interactions, and the phonological output system as the locus of the WF x WT and the SND x WT interactions. Additivity between INST and WT supports the notion that these variables affect separable systems, and a WF x SND interaction supports a common locus of their effects. These results support a dual-route cascaded model over parallel processing models of basic reading. We also examined response duration (RD) in these data by recording and hand-marking vocal responses, which provides evidence that reading processes are ongoing even after the initiation of a vocal response, and supports the notion that the more lexically a word is read, the shorter the RD. As such, the effects of WT and INST on RD were opposite to their effects on RT. Given the dissociating effects between RT and RD, these results provide new challenges to all models of basic reading processes. Experiments on picture and word identification (Experiments 3 and 4) involved localizing common systems and connections between these processes, and served to extend the dual-route model of reading. These experiments examined naming RT and RD for exception and regular words, and their corresponding pictures. The pattern of joint effects on RT among Format (pictures, words), Picture-Orthography Agreement, WF, and WT (regular, exception) supported a triple-route cascaded model. The results suggest the orthographic lexical system is accessed for both picture and word naming, and demonstrated a dissociation between regular and exception words on RT versus RD, whereas pictures consistently yielded an exception item advantage for both measures. Experiment 4 examined Arabic digits and their corresponding number words, and found that Arabic digits produce shorter RDs than number words. In general, the results suggest that the picture and word identification systems are strongly coupled between the picture memory system and the orthographic lexical system, particularly for items that rely on “whole-word” lexical representations. We argue that RD provides a wider window for exploring cognition, and a converging measure of lexical processing, which must be considered when studying basic identification processes of any stimulus type. The development of a comprehensive model of basic reading processes will help identify behavioural markers of normal reading processes, and will serve to advance research on basic word recognition. In addition, given that a broad definition of ‘literacy’ should include picture processing, the development of a model that includes picture processing will serve to advance research on how reading and picture processing interact with each other, which may be critical for individuals with low literacy skills

Semantic Priming Effects in Lexical Ambiguity Resolution

The study addresses a number of issues related to the effects of biasing semantic contexts on the processing of words with more than one meaning (homographs). Biasing contexts have been taken to either constrain “lexical access” to a contextually relevant meaning of a homograph (selective access), or to exert a selective effect only after access to all, or some subset of, the meanings of a homograph (multiple access). Recent findings based on the two-factor theory of attention (Posner & Snyder, 1975a) suggest that lexical access occurs in two stages, where the first stage involves automatic activation of all meanings and the second involves a rapid attentional selection of the contextually relevant meaning. A three word priming paradigm (Schvaneveldt, Meyer, & Becker, 1976) was employed to test the stages hypothesis. Subjects were required to name only the final target word, and their reaction time was the dependent variable. The critical trials involved presentation of the two word primes, where the first prime was a word related to one meaning of the second prime, which was a homograph. The comparison of most interest was between targets that were semantically congruent or incongruent with the biased homograph (e.g., oar-row-PADDLE and oar-row-COLUMN, respectively). These conditions were compared to two baselines: One employing two neutral primes (e.g., xxxxx-xxxxx-PADDLE), and one employing the biased homograph followed by an unrelated target (e.g., oar-row-GREEN). The stimulus onset asynchtrony (SOA) of the homograph was varied, as well as the strategies that subjects were instructed to use in attending to the context stimuli. Some evidence was found for the stages view of ambiguity resolution: At brief SOAs, congruent and incongruent targets were facilitated, whereas at a longer SOA, facilitation was significantly reduced for incongruent targets. Attentional strategies had less effect than anticipated. Also, results with the neutral baseline were discrepant with earlier findings. Discussion focused on the research hypotheses and characteristics of the naming task that might account for the discrepant findings. A brief theoretical overview concluded

Reading aloud boosts connectivity through the putamen

Functional neuroimaging and lesion studies have frequently reported thalamic and putamen activation during reading and speech production. However, it is currently unknown how activity in these structures interacts with that in other reading and speech production areas. This study investigates how reading aloud modulates the neuronal interactions between visual recognition and articulatory areas, when both the putamen and thalamus are explicitly included. Using dynamic causal modeling in skilled readers who were reading regularly spelled English words, we compared 27 possible pathways that might connect the ventral anterior occipito-temporal sulcus (aOT) to articulatory areas in the precentral cortex (PrC). We focused on whether the neuronal interactions within these pathways were increased by reading relative to picture naming and other visual and articulatory control conditions. The results provide strong evidence that reading boosts the aOT–PrC pathway via the putamen but not the thalamus. However, the putamen pathway was not exclusive because there was also evidence for another reading pathway that did not involve either the putamen or the thalamus. We conclude that the putamen plays a special role in reading but this is likely to vary with individual reading preferences and strategies

New Levels of Language Processing Complexity and Organization Revealed by Granger Causation

Granger causation analysis of high spatiotemporal resolution reconstructions of brain activation offers a new window on the dynamic interactions between brain areas that support language processing. Premised on the observation that causes both precede and uniquely predict their effects, this approach provides an intuitive, model-free means of identifying directed causal interactions in the brain. It requires the analysis of all non-redundant potentially interacting signals, and has shown that even “early” processes such as speech perception involve interactions of many areas in a strikingly large network that extends well beyond traditional left hemisphere perisylvian cortex that play out over hundreds of milliseconds. In this paper we describe this technique and review several general findings that reframe the way we think about language processing and brain function in general. These include the extent and complexity of language processing networks, the central role of interactive processing dynamics, the role of processing hubs where the input from many distinct brain regions are integrated, and the degree to which task requirements and stimulus properties influence processing dynamics and inform our understanding of “language-specific” localized processes

Integrating perceptual, semantic and syntactic information in sentence production

The experimental work and the theoretical model presented in this thesis explore the behaviour of the sentence production system in perceptually, conceptually, and syntactically changing environments across languages. Nine experiments examine how speakers of different languages integrate available perceptual, conceptual, and syntactic information during production of sentences. Such integration occurs under the global control of canonical causality and automated syntax. Analysis of speakers' performance in perceptually manipulated setting demonstrated that perceptual motivations for word order alternation are relatively weak and limited to the initial event apprehension. In addition, salience-driven choices of word order are realized differently in different syntactic structures and in languages with different grammatical systems. Combining perceptual and conceptual priming paradigms did not substantially improve cueing efficiency. Contrasting, early availability of lexical and syntactic information led to the most consistent alternation of the work order. I conclude that the uptake of perceptual information does not directly influence structural processing. General cognitive processes, such as attentional control and higher memorial activation actively contribute to the concept's accessibility status, but the syntactic organization of a spoken sentence constitutes a relatively independent psychological reality that can be realized partially as a product of the aforementioned operations but does not directly depend on them