The question of whether words can be identified without spatial attention has been a topic of considerable interest over the last five and a half decades, but the literature has yielded mixed conclusions. Some studies show substantial effects of distractor words which are argued to appear outside of spatial attention, whereas a small number of other studies show no evidence of such effects. I argue that at least some of the discrepant results can be understood in terms of failures to optimally focus attention at the cued location. The present experiments manipulated the proportion of valid trials to encourage distributed (Experiments 1 and 3) or focused (Experiments 2 and 4) spatial attention. Participants read aloud a target word, and the impact of a simultaneously presented distractor word was assessed. Semantic and repetition distractor effects were present when conditions promoted distributed spatial attention, but distractor effects were absent when conditions promoted focused spatial attention. These data are consistent with the proposal that (1) the allocation of spatial attention across displays is strongly context-dependent and (2) spatial attention is a necessary preliminary to lexical/semantic processing.

The question of whether words can be identified without spatial attention has been a topic of considerable interest over the last five and a half decades, but the literature has yielded mixed conclusions. Some studies show substantial effects of distractor words which are argued to appear outside of spatial attention, whereas a small number of other studies show no evidence of such effects. I argue that at least some of the discrepant results can be understood in terms of failures to optimally focus attention at the cued location. The present experiments manipulated the proportion of valid trials to encourage distributed (Experiments 1 and 3) or focused (Experiments 2 and 4) spatial attention. Participants read aloud a target word, and the impact of a simultaneously presented distractor word was assessed. Semantic and repetition distractor effects were present when conditions promoted distributed spatial attention, but distractor effects were absent when conditions promoted focused spatial attention. These data are consistent with the proposal that (1) the allocation of spatial attention across displays is strongly context-dependent and (2) spatial attention is a necessary preliminary to lexical/semantic processing.

The process of generating a phonological code from print is widely described as automatic. This claim is tested in Chapter 1 by assessing whether phonological recoding uses central attention in the context of the Psychological Refractory Period (PRP) paradigm. Task 1 was a tone discrimination task and Task 2 was reading aloud. Nonword letter length and grapheme-phoneme complexity yielded additive effects with SOA in Experiments 1 and 2 suggesting that <em>assembled phonology</em> uses central attention. Neighborhood density (N) yielded additive effects with SOA in Experiments 3 and 4, suggesting that one form of lexical contribution to phonological recoding also uses central attention. Taken together, the results of these experiments are <em>inconsistent</em> with the widespread claim that phonological codes are computed automatically. Chapter 2 begins by reconsidering the utility of ?automaticity? as an explanatory framework. It is argued that automaticity should be replaced by accounts that make more specific claims about how processing unfolds. Experiment 5 yielded underadditivity of long-lag word repetition priming with decreasing SOA, suggesting that an early component of the lexical contribution to phonology does not use central attention. There was no evidence of Task 1 slowing with decreasing SOA in Experiments 6 and 7, suggesting that phonological recoding processes are postponed until central attention becomes available. Theoretical development in this field (and others) will be facilitated by abandoning the idea that skilled performance inevitably means that all the underlying processes are automatic.

Two semantic priming experiments in the context of lexical decision are reported that examine the joint effects of stimulus quality, semantic context, and strength of association when all these factors are intermixed in a block of trials. A three-way interaction is seen in both experiments in which the typical interaction between semantic context and stimulus quality is eliminated when the strength of association between prime-target pairs is weak. The results support a role for a control mechanism that makes use of local information available within a trial, in addition to a global control mechanism that operates across a block of trials. The interaction between semantic context and stimulus quality when prime-target pairs are strongly related is attributed to the presence of feedback from the semantic system to the lexical system whereas additive effects of semantic context and stimulus quality is attributed to this feedback being eliminated such that semantic and lexical levels are functionally separate modules.

The process of generating a phonological code from print is widely described as automatic. This claim is tested in Chapter 1 by assessing whether phonological recoding uses central attention in the context of the Psychological Refractory Period (PRP) paradigm. Task 1 was a tone discrimination task and Task 2 was reading aloud. Nonword letter length and grapheme-phoneme complexity yielded additive effects with SOA in Experiments 1 and 2 suggesting that <em>assembled phonology</em> uses central attention. Neighborhood density (N) yielded additive effects with SOA in Experiments 3 and 4, suggesting that one form of lexical contribution to phonological recoding also uses central attention. Taken together, the results of these experiments are <em>inconsistent</em> with the widespread claim that phonological codes are computed automatically. Chapter 2 begins by reconsidering the utility of ?automaticity? as an explanatory framework. It is argued that automaticity should be replaced by accounts that make more specific claims about how processing unfolds. Experiment 5 yielded underadditivity of long-lag word repetition priming with decreasing SOA, suggesting that an early component of the lexical contribution to phonology does not use central attention. There was no evidence of Task 1 slowing with decreasing SOA in Experiments 6 and 7, suggesting that phonological recoding processes are postponed until central attention becomes available. Theoretical development in this field (and others) will be facilitated by abandoning the idea that skilled performance inevitably means that all the underlying processes are automatic.

Two semantic priming experiments in the context of lexical decision are reported that examine the joint effects of stimulus quality, semantic context, and strength of association when all these factors are intermixed in a block of trials. A three-way interaction is seen in both experiments in which the typical interaction between semantic context and stimulus quality is eliminated when the strength of association between prime-target pairs is weak. The results support a role for a control mechanism that makes use of local information available within a trial, in addition to a global control mechanism that operates across a block of trials. The interaction between semantic context and stimulus quality when prime-target pairs are strongly related is attributed to the presence of feedback from the semantic system to the lexical system whereas additive effects of semantic context and stimulus quality is attributed to this feedback being eliminated such that semantic and lexical levels are functionally separate modules.

Letter position plays an important role in lexical access. But are some positions more important than the others? Findings from numerous studies support the notion that in lexical access, initial letters produce strongest activation, which weakens towards the end of the word. In order to create a metric for computing the activation produced by each letter position in a correctly spelled word versus a word in which some or all letters are transposed, the formula for calculating a word's orthographic match coefficient (OMC) was developed and tested. Utilizing the masked priming paradigm and a lexical decision task, Experiments 1-5 test the accuracy and reliability of the OMC predictions, and look at neighborhood density in conjunction with different types of letter movement. Results from these experiments provide empirical support for the OMC as a reliable predictor of priming that involves transposed letters, and offer insight into possible mechanisms of word recognition.

The present dissertation aims to evaluate the phenomenon of visual masking as a tool for studying visual awareness focusing on two-alternative forced choice (2AFC) discrimination tasks. Two existing theories of masking - Bachmann's (1984) perceptual retouch theory and Marcel's (1983) recovery theory - are discussed along with the global neuronal workspace theory of awareness (Baars. 1989; Dehaene, Kerszberg, & Changeux, 1998). Performance accuracy on Semantic discrimination is compared to that on Orthographic discrimination as an indication of a potential difference between semantic and orthographic processing of masked word stimuli presented for 40 ms and 50 ms. This is further compared to an e-detection task previously used as an indicator of awareness in some masked priming experiments. Together, these tasks are further evaluated in terms of their relationship with participants' subjective reports collected in the form of confidence ratings. The implications and predictions drawn from the theories of masking and visual awareness as well as the notion of partial awareness (Kouider & Dupoux, 2001) are assessed taking into account the data obtained in the current experiments.The relevance of these data for masked priming is determined by performing a comparison between 2AFC discrimination and detection tasks, and the lexical decision task. An ERP study is also presented, in which Semantic and Orthographic discrimination as well as e-detection are paired with confidence ratings and electrophysiological recordings in search of an ERP component that can be correlated with both subjective (confidence) and objective (performance) measures of awareness. A binding account of visual awareness with special attention paid to visual masking is proposed and compared to the three existing theories.

Since it was introduced in Forster and Davis (1984), masked priming has been widely adopted in the psycholinguistic research on visual word recognition, but there has been little consensus on its actual mechanisms, i.e. how it occurs and how it should be interpreted. This dissertation addresses two different interpretations of masked priming, one based on the Interactive Activation Model (McClelland & Rumelhart, 1981), in which priming is seen as a result of persisting activation from the prime, the other based on the Entry Opening Model (Forster & Davis, 1984), which sees priming as a savings effect. Five experiments are reported testing contrasting hypotheses about the role of prime duration and prime-target asynchrony (SOA) in masked priming using both identity and form priming. Overall, this dissertation lends support to the Entry Opening Model, demonstrating that masked priming is essentially a savings effect, and that as such, it is determined by the SOA, not the prime duration per se.

Nous avons examiné à travers cinq études le rôle de la phonologie dans la reconnaissance de mots écrits chez des enfants tout-venant plus ou moins avancés dans l’apprentissage de la lecture. Pour cela, nous avons utilisé le paradigme de l’amorçage dans des versions visuelles, auditives et intermodales. Ce paradigme, à ce jour peu utilisé dans les études chez l’enfant, permet d’étudier, en temps réel et de manière précise, les processus phonologique et orthographiques engagés dans la reconnaissance de mots. Les études 1 et 2 montrent que chez les jeunes lecteurs, les représentations phonologiques du langage oral sont impliquées dans la lecture silencieuse de pseudomots, dans un format trait phonétique et dans la reconnaissance de mots familiers écrits, dans un format phonémique. L’étude 3 indique que le code phonologique contribue à la reconnaissance des mots de manière stable entre le CE2 et le CM2. Néanmoins, lorsque les représentations orthographiques sont peu spécifiées, la contribution du code phonologique est plus importante. Les études 4 et 5, en amorçage masqué visuel phonologique (O-P+ vs O-P-) et ortho-phonologique (O+P+ vs O+P-), montrent qu’au cours de la reconnaissance de mots familiers, les représentations phonologiques sont activées de manière automatique et ce dès le CE2. En revanche, l’activation automatique des représentations orthographiques semble apparaître plus tardivement dans le développement (CM2). Nos résultats suggèrent que lorsque le processus orthographique est fonctionnel mais pas encore pleinement efficace (CE2), la reconnaissance des mots écrits bénéficie de l’activation phonologique alors que, lorsque le processus est pleinement efficace (CM2), la reconnaissance des mots bénéficie de l’activation orthographique. Il semble donc que le développement du processus d’activation automatique des représentations phonologiques et le développement du processus d’activation automatique du lexique orthographique soient indépendants, le premier se développerait pleinement avant le second. / We conducted five studies to examine the role of phonological code in visual word recognition in children more or less advanced in learning to read. For that, we used the priming paradigm (in visual, auditory and inter modalities). This paradigm allows to study on-line and in precise manner, phonological and orthographic processes engaged in visual word recognition. The studies 1 and 2 indicate that, in Grade 3 and Grade 5, speech representations are involved in silent reading of pseudowords, in phonetic feature format and in visual familiar word recognition, in phonemic format. The study 3 indicates that phonological code contributes to visual word recognition in stable manner through Grade 3 and Grade 5. Nevertheless, when lexical orthographic representations are not well specified, phonological contribution is greater. The studies 4 and 5, in phonological (O-P+ vs O-P-) and ortho-phonological (O+P+ vs O+P-) visual masked priming, show that familiar visual word recognition involves phonological representations in automatic manner from Grade 3 to Grade 5. In contrast, automatic activation of orthographic representations seems to develop later (Grade 5). These results suggest that when orthographic process is functional but not fully effective (Grade 3), visual word recognition benefits from phonological activation whereas when orthographic process is fully effective (Grade 5), visual word recognition benefits from orthographic activation. That suggests that development of phonological automatic activation and development of orthographic automatic activation are independent. The process of phonological automatic activation is entirely developed earlier than the process of orthographic automatic activation.