Processing Of Word Stimuli Research Articles

Why cabbage and not carrot?: An investigation of factors affecting performance on spoken word to picture matching

Background: Word–picture matching tasks have been widely used to assess semantic processing in aphasia, but as yet have received little critical evaluation. Successful performance on a word–picture matching task employs several components of the language‐processing system, including lexical and semantic processing of word stimuli and the visual and semantic processing of picture stimuli. Hence it is not only semantic impairments that can affect performance on this task—breakdown in processing at any point from early auditory or visual processing of the word or visual perception of the pictures can affect accuracy. Consequently, performance on a word–picture matching task might be affected by psycholinguistic variables that pertain to any of these levels of processing, such as imageability, word length, word frequency, and the relationship of the distractors to the target.Aims: This study aimed to investigate the factors affecting word–picture matching performance, using one of the most widely used word–picture matching tasks (Subtest 47, Spoken word–picture matching, from PALPA; Kay, Lesser, & Coltheart, 1992).Methods and Procedures: The performance and error patterns of 54 participants with aphasia and 51 elderly control participants, who had completed spoken word–picture matching (subtest number 47) from PALPA, were evaluated. Correlation and regression analyses were used to investigate effects of psycholinguistic variables on performance (frequency, imageability, number of phonemes, semantic and visual similarity, and word association).Outcomes and Results: No variable was found to significantly affect control performance, due to ceiling effects. Imageability, semantic similarity, and word association affected the aphasic participant group performance. Six of the individuals with aphasia showed a significant effect on performance of at least one of four variables; imageability, semantic similarity, frequency, and word association.Conclusions: This study demonstrates that three psycholinguistic variables significantly affect the performance of both the group with aphasia and some individual participants with aphasia. It suggests that accuracy can be influenced not only by the nature of the relationship of the stimuli within the test but also by the individual level of language processing breakdown. Clinicians and researchers need to be mindful of this when using word–picture matching as the basis of their assessment of semantic processing in aphasia.

Temporal lobe abnormalities in semantic processing by criminal psychopaths as revealed by functional magnetic resonance imaging

We tested the hypothesis that psychopathy is associated with abnormalities in semantic processing of linguistic information. Functional magnetic resonance imaging (fMRI) was used to elucidate and characterize the neural architecture underlying lexico-semantic processes in criminal psychopathic individuals and in a group of matched control participants. Participants performed a lexical decision task in which blocks of linguistic stimuli alternated with a resting baseline condition. In each lexical decision block, the stimuli were either concrete words and pseudowords or abstract words and pseudowords. Consistent with our hypothesis, psychopathic individuals, relative to controls, showed poorer behavioral performance for processing abstract words. Analysis of the fMRI data for both groups indicated that processing of word stimuli, compared with the resting baseline condition, was associated with neural activation in bilateral fusiform gyrus, anterior cingulate, left middle temporal gyrus, right posterior superior temporal gyrus, and left and right inferior frontal gyrus. Analyses confirmed our prediction that psychopathic individuals would fail to show the appropriate neural differentiation between abstract and concrete stimuli in the right anterior temporal gyrus and surrounding cortex. The results are consistent with other studies of semantic processing in psychopathy and support the theory that psychopathy is associated with right hemisphere abnormalities for processing conceptually abstract material.

Neural pathways involved in the processing of concrete and abstract words.

The purpose of this study was to delineate the neural pathways involved in processing concrete and abstract words using functional magnetic resonance imaging (fMRI). Word and pseudoword stimuli were presented visually, one at a time, and the participant was required to make a lexical decision. Lexical decision epochs alternated with a resting baseline. In each lexical decision epoch, the stimuli were either concrete words and pseudowords, or abstract words and pseudowords. Behavioral data indicated that, as with previous research, concrete word stimuli were processed more efficiently than abstract word stimuli. Analysis of the fMRI data indicated that processing of word stimuli, compared to the baseline condition, was associated with neural activation in the bilateral fusiform gyrus, anterior cingulate, left middle temporal gyrus, right posterior superior temporal gyrus, and left and right inferior frontal gyrus. A direct comparison between the abstract and concrete stimuli epochs yielded a significant area of activation in the right anterior temporal cortex. The results are consistent with recent positron emission tomography work showing right hemisphere activation during processing of abstract representations of language. The results are interpreted as support for a right hemisphere neural pathway in the processing of abstract word representations.

Multi-Task Study of the Effects of Task Load and Gender on the Development of Visual Field Asymmetries

This study was designed to examine whether the developmental course of visual hemispheric asymmetry is affected by task load and whether gender differences occur with age. Three experiments were performed according to the additive structure of reaction time: “go/no-go” task, “choice-reaction-time” task, and “category-sort” task. Children in three different age groups (7- to 8-years, 10 years, and 13 year olds) were presented lists of words using a visual half-field procedure. Results revealed that in the go/no-go task (Experiment 1), left hemispheric superiority for processing of word stimuli was evident at all three developmental ages, but no gender differences appeared. However, in the choice-reaction-time task (Experiment 2), and the category-sort task (Experiment 3), left hemispheric superiority was displayed by 7- to 8- and 10-year-old males, but not by 13-year-old males. In contrast, girls did not show the left hemispheric advantage at any of the developmental ages. It was concluded that visual hemispheric asymmetry exists in children at an early age, but the magnitude of asymmetry is dependent on age, gender, and task load.

Modulation of semantic processing by spatial selective attention

The effects of spatial selective attention upon ERPs associated with the processing of word stimuli were investigated. While subjects maintained central eye fixation, ERPs were recorded to words presented to the left and right visual fields. In each of 6 runs, subjects focussed attention to alternate fields to perform a category-detection task. Pairs of semantically related and repeated words were embedded in the word lists presented to the attended and unattended visual fields. Consistent with prior studies, the P1-N1 visual ERP was larger when elicited by words in attended spatial locations. A large negative slow wave identified as N400 was elicited by attended, but not unattended, words. For attended words, N400 was smaller for semantically primed or repeated words. We concluded that spatial selective attention can modulate the degree to which words are processed, and that the cognitive processes associated with N400 are not automatic.