Semantic preview benefit in English: Individual differences in the extraction and use of parafoveal semantic information

While there is robust evidence that skilled readers of English extract and use orthographic and phonological information from the parafovea to facilitate word identification, semantic preview benefits are more elusive. We sought to establish whether individual differences in the extraction and/or use of parafoveal semantic information could account for this discrepancy. Ninety-nine adult readers were assessed on measures of reading and spelling ability and read sentences while their eye movements were recorded. The gaze-contingent boundary paradigm was used to manipulate the availability of relevant semantic and orthographic information in the parafovea. On average, readers showed a benefit from previews high in semantic feature overlap with the target. However reading and spelling ability yielded opposite effects on semantic preview benefit. High reading ability was associated with a semantic preview benefit that was equivalent to an identical preview on first-pass reading. High spelling ability was associated with a reduced semantic preview benefit despite an overall higher rate of skipping. These results suggest that differences in the magnitude of semantic preview benefits in English reflect constraints on extracting semantic information from the parafovea and competition between the orthographic features of the preview and target.Australian Research Counci

Parafoveal preview benefit in sentence reading: Independent effects of plausibility and orthographic relatedness

Recent evidence from studies using the gaze-contingent boundary paradigm suggests that parafoveal preview benefit is contingent on the fit between a preview word and the sentence context. We investigated whether this plausibility preview benefit is modulated by preview/target orthographic relatedness. Participants’ eye movements were recorded as they read sentences in which the parafoveal preview of a target word was manipulated. Non-identical previews were plausible or implausible continuations of the sentence that were either an orthographic neighbor of the target or unrelated to the target. First-pass reading measures showed a strong plausibility preview benefit. There was also a benefit from preview/target orthographic relatedness across reading measures. These two preview effects did not interact on any fixation measure. There was also no evidence that the relatedness effect was caused by misperception of an orthographically similar preview as the target word. These data highlight the existence of two independent mechanisms underlying preview effects: a benefit from the contextual fit of the preview word in the sentence and a benefit from the sublexical overlap between the preview and target word.Australian Research Counci

Is semantic preview benefit due to relatedness or plausibility?

There is increasing evidence that skilled readers of English benefit from processing a parafoveal preview of a semantically related word. However, in previous investigations of semantic preview benefit using the gaze-contingent boundary paradigm the semantic relatedness between the preview and target has been confounded with the plausibility of the preview word in the sentence. In the present study, preview relatedness and plausibility were independently manipulated in neutral sentences read by a large sample of skilled adult readers. Participants were assessed on measures of reading and spelling ability to identify possible sources of individual differences in preview effects. The results showed that readers benefited from a preview of a plausible word, regardless of the semantic relatedness of the preview and the target. However, there was limited evidence of a semantic relatedness benefit when the plausibility of the preview was controlled. The plausibility preview benefit was strongest for low proficiency readers, suggesting that poorer readers were more likely to program a forward saccade based on information extracted from the preview. High proficiency readers showed equivalent disruption from all non-identical previews suggesting that they were more likely to suffer interference from the orthographic mismatch between preview and target.Australian Research Counci

Spelling ability selectively predicts the magnitude of disruption in unspaced text reading

We examined the effect of individual differences in written language proficiency on unspaced text reading in a large sample of skilled adult readers who were assessed on reading comprehension and spelling ability. Participants’ eye movements were recorded as they read sentences containing a low or high frequency target word, presented with standard interword spacing, or in one of three unsegmented text conditions that either preserved or eliminated word boundary information. The average data replicated previous studies: unspaced text reading was associated with increased fixation durations, a higher number of fixations, more regressions, reduced saccade length, and an inflation of the word frequency effect. The individual differences results provided insight into the mechanisms contributing to these effects. Higher reading ability was associated with greater overall reading speed and fluency in all conditions. In contrast, spelling ability selectively modulated the effect of interword spacing with poorer spelling ability predicting greater difficulty across the majority of sentence- and word-level measures. These results suggest that high quality lexical representations allowed better spellers to extract lexical units from unfamiliar text forms, inoculating them against the disruptive effects of being deprived of spacing information.Australian Research Counci

Groundwater and Intergovernmental Relations in the Southern San Joaquin Valley, California

25 pages (includes maps)

Individual differences in automatic semantic priming

This research investigated whether automatic semantic priming is modulated by individual differences in lexical proficiency. A sample of 89 skilled readers, assessed on reading comprehension, vocabulary and spelling ability, were tested in a semantic categorisation task that required classification of words as animals or non-animals. Target words were preceded by brief (50 ms) masked semantic primes that were either congruent or incongruent with the category of the target. Congruent primes were also selected to be either high (e.g., hawk EAGLE, pistol RIFLE) or low (e.g., mole EAGLE, boots RIFLE) in feature overlap with the target. ‘Overall proficiency’, indexed by high performance on both a ‘semantic composite’ measure of reading comprehension and vocabulary and a ‘spelling composite’, predicted stronger congruence priming from both high and low feature overlap primes for animal exemplars, but only predicted priming from low overlap primes for non-exemplars. Classification of high frequency non-exemplars was also significantly modulated by an independent ‘spelling-meaning’ factor, indexed by differences between the semantic and spelling composites, which appeared to tap sensitivity to semantic relative to orthographic feature overlap between the prime and target. These findings show that higher lexical proficiency predicts stronger automatic semantic priming and suggest that individual differences in lexical quality modulate the division of labor between orthographic and semantic processing in early lexical retrieval.Australian Research Counci

Birnbaum’s measure of component importance for noncoherent systems

Importance analysis of noncoherent systems is limited, and is generally inaccurate because all measures of importance that have been developed are strictly for coherent analysis. This paper considers the probabilistic measure of component importance developed by Birnbaum (1969). An extension of this measure is proposed which enables noncoherent importance analysis. As a result of the proposed extension the average number of system failures in a given interval for noncoherent systems can be calculated more efficiently. Furthermore, because Birnbaum’s measure of component importance is central to many other measures of importance; its extension should make the derivation of other measures possible

Importance measures for non-coherent-system analysis

Component importance analysis is a key part of the system reliability quantification process. It enables the weakest areas of a system to be identified and indicates modifications, which will improve the system reliability. Although a wide range of importance measures have been developed, the majority of these measures are strictly for coherent system analysis. Non-coherent systems can occur and accurate importance analysis is essential. This paper extends four commonly used measures of importance, using the noncoherent extension of Birnbaum’s measure of component reliability importance. Since both component failure and repair can contribute to system failure in a noncoherent system, both of these influences need to be considered. This paper highlights that it is crucial to choose appropriate measures to analyze component importance. First the aims of the analysis must be outlined and then the roles that component failures and repairs can play in system state deterioration can be considered. For example, the failure/repair of components in safety systems can play only a passive role in system failure, since it is usually inactive, hence measures that consider initiator importance are not appropriate to analyze the importance of these components. Measures of importance must be chosen carefully to ensure analysis is meaningful and useful conclusions can be drawn

Calculating the failure intensity of a non-coherent fault tree using the BDD technique.

This paper considers a technique for calculating the unconditional failure intensity of any given non-coherent fault tree. Conventional Fault Tree Analysis (FTA) techniques involve the evaluation of lengthy series expansions and approximations are unavoidable even for moderate sized fault trees. The Binary Decision Diagram (BDD) technique overcomes some of the shortfalls of conventional FTA techniques enabling efficient and exact quantitative analysis of both coherent and non-coherent fault trees