Differences Between Left and Right Hemispheric Performance on a Word Generation Task Among Varying Levels of Non-Verbal Intelligence Scores

Using archival data, this study examined the differences between left and right hemisphere performance on a word generation task among participants with varying non-verbal intelligence scores. Participants in the original study completed the Test of Non-verbal Intelligence 4th edition (TONI-4) and a word generation task in which word-stems (the beginning 3 letters of a word) were presented to either the left or right visual field. Additionally, wordstems were divided into two conditions: easy (several completions, common words) and difficult (few completions, uncommon words.) Participants were then to complete the word. In the current study, performance of the participants was determined by using both the speed and accuracy of responses. Based on their TONI-4 score, participants were divided into groups of high and low non-verbal intelligence. Within each group, left hemisphere performance in the difficult condition was compared to right hemisphere performance in the difficult condition. Additionally, left hemisphere performance was compared to right hemisphere performance among the higher (HNV) and the lower (LNV) non-verbal intelligence score groups. It was hypothesized that individuals within the HNV intelligence group would demonstrate increased right hemisphere performance when compared to left hemisphere performance on a difficult word generation task. It was also hypothesized that individuals within the HNV intelligence group would demonstrate increased right hemisphere performance when compared to the individuals in the LNV intelligence group. Analyses indicated that in both the left and right hemispheres, there was a significant difference in reaction time between the higher and lower non-verbal IQ groups. Among both groups of participants, there was a significant difference between left hemisphere performance and right hemisphere performance, such that the right hemisphere was more accurate and responded more rapidly than the left hemisphere. Observing the differences between hemisphere performance on a word-stem completion task within HNV and LNV intelligence groups can lead clinicians and researchers to have a better understanding of the relationship between non-verbal intelligence and language, make predictions about areas of relative strength in individuals, and identify patients of potential risks