The effects of immediate stimulus repetition on reaction time and event-related potentials in tasks of different complexity.

Examined the effect of immediate stimulus repetition in lexical decision, face recognition, letter search, face/nonface discrimination, and word/number discrimination tasks using reaction time (RT), accuracy, and event-related brain potential (ERP) measures. Repetition facilitated performance in all tasks and for all stimulus types. However, ERPs were strongly affected by repetition only in lexical decision, face recognition, and letter search, when relatively long stimulus analysis and decision making processes were required. The ERP repetition effect consisted of a significant increase in P300 amplitude and a shortening of its latency. Repetition also resulted in the attenuation of a negative component that was tentatively identified as N400. These results suggest that immediate repetition facilitates stimulus identification and eliminates the need for stimulus analysis processes including access to semantic memory while making categorical decisions. While both factors affected RT, ERPs were modulated primarily by the elimination of the need to access to semantic memory and by the consequent speeding of categorical decision processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New evidence for phonological processing during visual word recognition: The case of Arabic.

Lexical decision and naming were examined with words and pseudowords in literary Arabic and with transliterations of words in a Palestinian dialect that has no written form. Although the transliterations were visually unfamiliar, they were not easily rejected in lexical decision, and they were more slowly accepted in phonologically based lexical decision. Naming transliterations of spoken words was slower than naming of literary words and pseudowords. Apparently, phonological computation is mandatory for both lexical decision and naming. A large frequency effect in both lexical decision and naming suggests that addressed phonology is an option for familiar orthographic patterns. The frequency effect on processing transliterations indicated that lexical phonology is involved with prelexical phonological computation even if addressed phonology is not possible. These data support a combination between a cascade-type process, in which partial products of the grapheme-to-phoneme translation activate phonological units in the lexicon, and an interactive model, in which the activated lexical units feed back, shaping the prelexical phonological computation process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention mechanisms mediate the syntactic priming effect in auditory word identification.

Investigated the syntactic priming effect and the involvement of attention in that process by testing identification of white noise-masked Hebrew words. Targets were either syntactically congruent or syntactically incongruent with the structure of the sentence. Relative to a neutral condition, similar facilitation and inhibition was found for congruent and incongruent targets, respectively. When syntactic congruency was blocked, the inhibition was attenuated, whereas the facilitation remained the same. A 350-msec silent interstimulus interval between context and target increased inhibition without affecting facilitation. It is suggested that both the facilitation and the inhibition effects of syntactic priming are based on a veiled controlled process of generating expectations. The inhibition results from a controlled process of reevaluation that requires additional attention resources. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention constraints of semantic activation during visual word recognition.

The reduction of semantic priming following letter search of the prime suggests that semantic activation can be blocked if attention is allocated to the letter level during word processing. Is this true even for the very fast-acting component of semantic activation? To test this, the authors explored semantic priming of lexical decision at stimulus onset asynchronies (SOAs) of either 200 or 1000 ms. Following semantic prime processing, priming occurred at both SOAs. In contrast, no priming occurred at the long SOA following letter-level processing. Of greatest interest, at the short SOA there was priming following the less demanding consonant/vowel task but not following the more attention-demanding letter search task. Hence, semantic activation can occur even when attention is directed to the letter level, provided there are sufficient resources to support this activation. The authors conclude that the default setting during word recognition is for fast-acting activation of the semantic system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing phonological and semantic ambiguity: Evidence from semantic priming at different SOAs.

Disambiguation of heterophonic and homophonic homographs was investigated in Hebrew using semantic priming. Ambiguous primes were followed by unambiguous targets at 100 msec, 250 msec, and 750 msec stimulus onset asynchrony (SOA). Lexical decision for targets related to the dominant phonological alternatives of heterophonic homographs was facilitated at all SOAs. Targets related to subordinate alternatives were facilitated only at SOAs of 250 msec or longer. When the primes were homophonic homographs, semantic relationship facilitated lexical decision to targets at all SOAs regardless of the dominance of the meaning to which the targets were related. These data can be accounted for by assuming multiple lexical entries for heterophonic homographs, single lexical entries for homophonic homographs, and phonological mediation of accessing meanings. Language-specific factors probably account for the long-lasting activation of subordinate meanings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrophysiological evidence for task effects on semantic priming in auditory word processing

A large-scale trial investigated the possibility of eradicating G.m.centralis from a traditional cattle rearing area using odour-baited targets at a reduced overall target density from 4 to 0.5-2.3 per km2, thus cutting down initial material costs by about 50%. Only the periphery of what was thought to be prime tsetse habitat (dense woodland) was treated with targets. These were all black or blue/black cloth (1.8 x 1 m), sprayed with deltamethrin suspension concentrate and baited with butanone and/or acetone (40-130 mg/h) and 1-octen-3-ol (0.5 mg/h). Although fly catches from traps and flyrounds initially dropped by approximately 3% per day and trypanosomiasis cases declined by 99% within a year, eradication was not achieved, so that more targets were deployed at a later stage. Although initially cheaper, the option of using reduced target densities proved financially unattractive because of prolonged periods of target maintenance prior to eradication. Revised strategies for tsetse control with odour-baited, insecticide-impregnated targets in west Zambia are presented.     

Stimulus type, level of categorization, and spatial-frequencies utilization: Implications for perceptual categorization hierarchies.

The type of visual information needed for categorizing faces and nonface objects was investigated by manipulating spatial frequency scales available in the image during a category verification task addressing basic and subordinate levels. Spatial filtering had opposite effects on faces and airplanes that were modulated by categorization level. The absence of low frequencies impaired the categorization of faces similarly at both levels, whereas the absence of high frequencies was inconsequential throughout. In contrast, basic-level categorization of airplanes was equally impaired by the absence of either low or high frequencies, whereas at the subordinate level, the absence of high frequencies had more deleterious effects. These data suggest that categorization of faces either at the basic level or by race is based primarily on their global shape but also on the configuration of details. By contrast, basic-level categorization of objects is based on their global shape, whereas category-specific diagnostic details determine the information needed for their subordinate categorization. The authors conclude that the entry point in visual recognition is flexible and determined conjointly by the stimulus category and the level of categorization, which reflects the observer’s recognition goal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Variable cerebral responses to equally distinct deviance in four auditory dimensions: a mismatch negativity study

This paper uses regression models to investigate the efficacy of the seat belt regulation as well as the circuit training and testing system in reducing traffic related fatalities in Singapore. The effectiveness of alcohol breathalysers was also studied. Results suggest that the seat belt regulation does not have any impact on traffic fatalities. The use of breathalysers was found to be effective in reducing occupant fatalities. The circuit training and testing system, which aims to equip new pools of motorists with appropriate driving or riding skills, was found to be effective in reducing non-occupant fatalities and total fatalities.     

Orthography and phonology in lexical decision: Evidence from repetition effects at different lags.

Full- and partial- (orthographic or phonemic) repetition effects for Hebrew voweled and unvoweled words and nonwords were examined at Lags 0 and 15 between the first and the second presentations. For voweled words, phonemic and orthographic partial-repetition effects were equivalent at Lag 0, each about half the size of the full-repetition effect. At Lag 15, the full-repetition effect was reduced to the size of phonemic repetition, which was as big as it was at Lag 0. In contrast, the orthographic repetition effect disappeared. For unvoweled words, the phonemic repetition effect was significant only at Lag 0, whereas the full-repetition effect was significant at both lags. Lexical decisions for both voweled and unvoweled nonwords were facilitated only by full repetition at Lag 0. It was concluded that addition of vowel marks attracted the subjects' attention and, therefore, lexical decisions for voweled stimuli were mediated by phonemic analysis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strategies for visual word recognition and orthographical depth: A multilingual comparison.

We investigated the psychological reality of the concept of orthographical depth and its influence on visual word recognition by examining naming performance in Hebrew, English, and Serbo-Croatian. Experiment 1 revealed that the lexical status of the stimulus (high-frequency words, low-frequency words, and nonwords) significantly affected naming in Hebrew (the deepest of the three orthographies). This effect was only moderate in English and nonsignificant in Serbo-Croatian (the shallowest of the three orthographies). Moreover, only in Hebrew did lexical status have similar effects on naming and lexical decision performance. Experiment 2 revealed that semantic priming effects in naming were larger in Hebrew than in English and completely absent in Serbo-Croatian. Experiment 3 revealed that a large proportion of nonlexical tokens (nonwords) in the stimulus list affects naming words in Hebrew and in English, but not in Serbo-Croatian. Results support the orthographical depth hypothesis and suggest, in general, that in shallow orthographies phonology is generated directly from print, whereas in deep orthographies phonology is derived from the internal lexicon. (PsycINFO Database Record (c) 2010 APA, all rights reserved)