Poster A67, Saturday, March 25, 5:00 – 7:00 pm, Pacific Concourse
Evidence for Right Hemisphere Role in Semantic Exemplar Generation
Alessandra Macbeth1, Adam Felton1, Christine Chiarello1; 1University of California, Riverside
Prior research has indicated a right hemisphere (RH) role in the activation of distant semantic meanings during language comprehension. Here we examined whether similar asymmetries also exist during semantic production. Two hundred subjects completed an exemplar generation task, where category words (e.g., animal) were presented to left or right visual fields (LVF, RVF), and participants verbally generated one exemplar for each word. We measured uniqueness and latent semantic analysis (LSA; computes semantic distance) scores for each responses given. Uniqueness scores were computed by summing the number of individuals who gave each exemplar response, and then assigning that value to each item. Lower scores indicate more unique responses (e.g., for “citrus”, “grapefruit” (uniqueness=5) was a more unique response than “orange” (uniqueness=148). For uniqueness, a mixed ANOVA revealed main effects of VF, F(1,198)=169.0, p<.001 (mean LVF=41.18, RVF=48.37), and sex, F(1,198)=6.65, p=.01 (mean Males=43.86, Females=45.85), but no interaction. A similar analysis for LSA uncovered a main effect of VF, F(1,198)=35.62, p< .001 (mean LVF=.38, RVF=.41), but no main effect of sex or interaction. Our results indicate that participants produced more unique and semantically distant exemplar responses to LVF/RH category words, and males produced more unique responses overall. We conclude that when processing is initiated by the right hemisphere, more semantically distant and unique exemplars are generated than for left hemisphere initiated processing, complementing findings from comprehension tasks. Therefore, a RH role in the accessibility of distant semantic meanings may influence word choice in some production tasks.
Topic Area: LANGUAGE: Semantic