Mental tug of war
How does grasping and language affect each other?
Previous studies have found an association between hand motor actions and speech function. The objective of this study was to investigate if verbal fluency tasks (word production) can affect grasping behaviour. We reasoned that the type of word would influence grasping behaviour differentially. Specifically, we hypothesized that when compared to nouns, the generation of verbs would interfere more with grasping because previous research has shown activation in primary motor cortex during verb comprehension. We recruited left- (n=15) and right-handers (n=24) to participate in this study.
Each participant was asked to perform a grasping task (LEGO building task), and a word fluency task both separately and simultaneously. The word fluency tasks consisted of noun and verb generation. Our results showed that overall, the number of times participants incorrectly grasped a block (place errors) while simultaneously producing verbs predicted the number of verbs produced while building; the more place errors made, the fewer verbs produced. This was not the case when producing nouns. To conclude, speech production, specifically of verbs interfere with manual action.