Which cognitive functions subserve clustering and switching in category fluency? Generalisations from an extended set of semantic categories using linear mixed-effects modelling

Abstract

Clustering and switching are hypothesised to reflect the automatic and controlled components in category fluency, respectively, but how they are associated with cognitive functions has not been fully elucidated, due to several uncertainties. (1) The conventional scoring method that segregates responses by semantic categories could not optimally dissociate the automatic and controlled components. (2) The temporal structure of individual responses, as characterised by mean retrieval time (MRT) and mean switching time (MST), has seldom been analysed alongside the more well-studied variables, cluster size (CS) and number of switches (NS). (3) Most studies examined only one to a few semantic categories, raising concerns of generalisability. This study built upon a distance-based automatic clustering procedure, referred to as temporal–semantic distance procedure, to thoroughly characterise the category fluency performance. Linear mixed-effects (LME) modelling was applied to re-examine the differential associations of clustering and switching with cognitive functions with a sample of 80 university students. Our results revealed that although lexical retrieval speed (LRS) is clearly the determining factor for effective clustering and switching, matrix reasoning and processing speed also have significant roles to play, possibly in the processes of identifying and validating the semantic relationships. Interestingly, total fluency score was accurately predicted by the four clustering/switching indices alone; including the cognitive variables did not significantly improve the prediction. These findings underline the importance of the clustering and switching indices in explaining the category fluency performance and the cognitive demands in category fluency.

Clustering and Switching in Verbal Fluency Across Varying Degrees of Cognitive Control Demands: Evidence From Healthy Bilinguals and Bilingual Patients With Aphasia

“…Additionally, it was hypothesized that FS switching performance would be predicted by language experience measures (language use questionnaire, or LUQ, metrics) as increased proficiency would lead to greater efficiency at implementing language control, resulting in less competition between the language control and semantic executive control levels. Finally, for BPWA, it was hypothesized that Raven’s Coloured Progressive Matrices (RCPM; Kertesz, 2006 ) scores, a measure of matrix reasoning ( Fong et al, 2020 ), would be predictive of performance on FS switching performance as better nonverbal cognitive function would lead to more controlled search processes as task demands increase.…”

Semantic fluency reveals reduced functional connectivity between subcategorical co-hyponyms in recent-onset inpatients with first-episode psychosis

“…Clustering and switching have been described as relatively automatic and controlled processes, respectively (Troyer & Moscovitch, 2006). Recent research shows that clustering and switching on SF are correlated with matrix reasoning and processing speed (Fong et al, 2020). Nonetheless, Vandek et al (2018) and Gabrić and Vandek (2020) found that clustering and switching on the tree, but not the animal task was associated with cognitive flexibility, indicating the existence of category specificities in clustering and switching.…”

“…Despite its frequent use, the cognitive and specific linguistic correlates of SF remain mostly unclear. Although the presumed working memory and executive functioning components of both SF and letter fluency are often emphasized (Amunts et al, 2020), studies suggest that both general cognitive and specific linguistic processing subserve performance on verbal fluency (Fong et al, 2020;Stielow & Stenneken, 2017). Nonetheless, which linguistic (or lexical) processes subserve verbal fluency remains likewise unclear.…”

Semantic fluency reveals reduced functional connectivity between subcategorical co-hyponyms in recent-onset inpatients with first-episode psychosis

“…Despite its frequent use, the cognitive and specific linguistic correlates of SF remain mostly unclear. Although the presumed working memory and executive functioning components of both SF and letter fluency are often emphasized (Amunts et al, 2020), studies suggest that both general cognitive and specific linguistic processing subserve performance on verbal fluency (Fong et al, 2020;Stielow & Stenneken, 2017). Nonetheless, which linguistic (or specifically semantic) processes subserve verbal fluency remains likewise unclear.…”

“…Clustering and switching have been described as relatively automatic and controlled processes, respectively (Troyer & Moscovitch, 2006). Recent research shows that clustering and switching on SF are correlated with matrix reasoning (reflects the ability to apply knowledge in resolving a novel problem; Raven's Standard Progressive Matrices) and processing speed (Fong et al, 2020). Nonetheless, Vandek et al (2018) and Gabrić and Vandek (2020) found that clustering and switching on the tree, but not the animal task was associated with cognitive flexibility, indicating the existence of category specificities in clustering and switching.…”