Complement coercion is not modulated by competition: Evidence from eye movements.

An eye-movement study examined the processing of expressions requiring complement coercion (J. Pustejovsky, 1995), in which a noun phrase that does not denote an event (e.g., the book) appears as the complement of an event-selecting verb (e.g., began the book). Previous studies demonstrated that these expressions are more costly to process than are control expressions that can be processed with basic compositional operations (L. Pylkkanen & B. McElree, 2006). Complement coercion is thought to be costly because comprehenders need to construct an event sense of the complement to satisfy the semantic restrictions of the verb (e.g., began writing the book). The reported experiment tests the alternative hypotheses that the cost arises from the need to select 1 interpretation from several or from competition between alternative interpretations. Expressions with weakly constrained interpretations (no dominant interpretation and several alternative interpretations) were not more costly to process than expressions with a strongly constrained interpretation (1 dominant interpretation and few alternative interpretations). These results are consistent with the hypothesis that the cost reflects the on-line construction of an event sense for the complement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing ambiguous verbs: Evidence from eye movements.

In 2 eye-tracking experiments, participants read verbs that had 2 (unrelated) meanings or 2 (related) senses in contexts that disambiguated before or after the verb, to the dominant or subordinate interpretation. A 3rd experiment used unambiguous verbs. The results indicated that the language processor used information about context in the early stages of resolving meaning ambiguities but only during integration for sense ambiguities. Effects of preference were delayed for both types of verbs. The results contrast with findings concerning the processing of nouns (e.g., K. Rayner & S. A. Duffy, 1986). For meaning ambiguities, the authors argue that delays in resolution allow both meanings to reach a high level of activation, thus reducing effects of frequency. For sense ambiguities, the authors argue that the processor does not access multiple senses but activates one underspecified meaning and uses context to home in on the appropriate sense. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimization of GEANT4 settings for Proton Pencil Beam Scanning simulations using GATE

This study reports the investigation of different GEANT4 settings for proton therapy applications in the context of Treatment Planning System comparisons. The GEANT4.9.2 release was used through the GATE platform. We focused on the Pencil Beam Scanning delivery technique, which allows for intensity modulated proton therapy applications. The most relevant options and parameters (range cut, step size, database binning) for the simulation that influence the dose deposition were investigated, in order to determine a robust, accurate and efficient simulation environment. In this perspective, simulations of depth-dose profiles and transverse profiles at different depths and energies between 100 and 230 MeV have been assessed against reference measurements in water and PMMA. These measurements were performed in Essen, Germany, with the IBA dedicated Pencil Beam Scanning system, using Bragg-peak chambers and radiochromic films. GEANT4 simulations were also compared to the PHITS.2.14 and MCNPX.2.5.0 Monte Carlo codes. Depth-dose simulations reached 0.3 mm range accuracy compared to NIST CSDA ranges, with a dose agreement of about 1% over a set of five different energies. The transverse profiles simulated using the different Monte Carlo codes showed discrepancies, with up to 15% difference in beam widening between GEANT4 and MCNPX in water. A 8% difference between the GEANT4 multiple scattering and single scattering algorithms was observed. The simulations showed the inability of reproducing the measured transverse dose spreading with depth in PMMA, corroborating the fact that GEANT4 underestimates the lateral dose spreading. GATE was found to be a very convenient simulation environment to perform this study. A reference physics-list and an optimized parameters-list have been proposed. Satisfactory agreement against depth-dose profiles measurements was obtained. The simulation of transverse profiles using different Monte Carlo codes showed significant deviations. This point is crucial for Pencil Beam Scanning delivery simulations and suggests that the GEANT4 multiple scattering algorithm should be revised.     

The processing of metonymy: Evidence from eye movements.

The authors investigated the time course of the processing of metonymic expressions in comparison with literal ones in 2 eye-tracking experiments. Experiment 1 considered the processing of sentences containing place-for-institution metonymies such as the convent in That blasphemous woman had to answer to the convent; it was found that such expressions were of similar difficulty to sentences containing literal interpretations of the same expressions. In contrast, expressions without a relevant metonymic interpretation caused immediate difficulty. Experiment 2 found similar results for place-for-event metonymies such as A lot of Americans protested during Vietnam, except that the difficulty with expressions without a relevant metonymic interpretation was somewhat delayed. The authors argue that these findings are incompatible with models of figurative language processing in which either the literal sense is accessed first or the figurative sense is accessed first. Instead, they support an account in which both senses can be accessed immediately, perhaps through a single under specified representation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Contextual Predictability and Transitional Probability on Eye Movements During Reading.

In 2 eye-movement experiments, the authors tested whether transitional probability (the statistical likelihood that a word precedes or follows another word) affects reading times and whether this occurs independently from contextual predictability effects. Experiment 1 showed early effects of predictability, replicating S. A. McDonald and R. C. Shillcock's (2003a) finding that words with a high transitional probability (defeat following accept) are read faster than words with a low transitional probability (losses following accept). However, further analyses suggested that the transitional probability effect was likely due to differences in predictability rather than transitional probability. Experiment 2, using a better controlled set of items, again showed an effect of predictability, but no effect of transitional probability. The authors conclude that effects of transitional probability are part of regular predictability effects. Their data also show that predictability effects are detectable very early in the eye-movement record and between contexts that are weakly constraining. (PsycINFO Database Record (c) 2010 APA, all rights reserved)