The effect of cognitive load on linguistic fluency, lexical production, and emotional polarity: An exploratory study on self-directed French

Abstract Cognitive load refers to the mental resources available in working memory, which can vary due to, e.g., the inherent complexity of a task. Studies have investigated the effect of a higher cognitive demand on speech, either on fluency, lexical use or linguistic display of emotions. Fewer have investigated all these parameters jointly, and most focus on English. Here we manipulate working memory load with an image-depiction task with or without access to the image and investigate whether cognitive load impacts speech production in French, i.e., correlates with both fluency metrics (number of word tokens and lemmas, lemma-token ratio, counts and rates of filled pauses, interruptions and repetitions) and/or with lexical metrics (use of words from a given lexical field or with a given connotation). Our results show that, compared to their peers in the low cognitive load condition (with access to the image), speakers under high cognitive load (who describe the image from memory) indeed tend to use more disfluencies but show little differences in the use of specific vocabulary or in emotional words. Although the absence of lexical differences may be due to inherent language- or task-specific differences, the confirmation that an increase in cognitive load implies an increase in disfluency indicates that at least this one parameter is a cross-linguistic indicator of speech production under high cognitive load.