The mind's eye in your creative hands: The role of hand gestures and mental imagery in creative thinking

Gestures are an integral part of human communication, also playing significant self-oriented functions, such as activating the speaker's verbal lexicon and maintaining visuospatial imagery. Despite their recognized roles in facilitating cognitive processes, the impact of gestures on creative thinking, and particularly within the context of individual differences and bilingualism, is not fully understood. Across three studies, I examined the multifaceted role of gestures in both convergent and divergent thinking, considering individual differences in mental imagery skills and within the context of bilingualism. In Chapter 2, I aimed to determine whether gestures contributed to verbal and visual convergent thinking (a creative process related to finding the best answer to a problem) in young adults, while controlling for their mental imagery skills. Participants were assessed on verbal and visual convergent thinking tasks, with gestures being either spontaneous or encouraged. The results showed that the interaction between gestures and mental imagery skills played a role in verbal convergent thinking but not in visual convergent thinking. Specifically, a negative association was found between overall gesture frequency and verbal convergent thinking for individuals with low mental imagery skills, whereas a positive association was observed for those with high mental imagery skills. Representational gestures were found to benefit verbal convergent thinking for most participants, except those with low mental imagery and no prior task experience. Interestingly, beat gestures (i.e., rhythmic hand movements without semantic content) were also associated with better convergent thinking as long as individuals had high imagery skills and previous task experience. Otherwise, they were negatively associated with convergent thinking. These findings suggest that whether gestures benefit or impair convergent thinking would depend on factors such as imagery skills, types of gestures executed, and previous task experience. Chapter 3 delved into the role of iconic gestures in verbal divergent thinking, a creative process that involves generating numerous novel ideas. I hypothesized that iconic gesture use would enhance divergent thinking in young adults, particularly those with high mental imagery skills as shown in Chapter 2. Participants' verbal divergent thinking, including fluency (number of ideas), originality (uniqueness of ideas), flexibility (number of idea categories), and elaboration (number of details) were evaluated in both gesture-spontaneous and gesture-encouraged conditions. The results demonstrated that producing iconic gestures in the gesture-encouraged condition positively predicted fluency, originality, and elaboration. Even in the gesture-spontaneous condition, iconic gestures positively predicted elaboration but negatively predicted flexibility. Mental imagery skills did not play a role in gestures and divergent thinking, suggesting that iconic gestures enhance almost all aspects of divergent thinking regardless of mental imagery. Chapter 4 investigated the influence of language context on creative thinking, vividness of mental imagery, and the use of representational hand gestures among Turkish-English bilingual speakers. Participants completed verbal divergent and convergent thinking tasks in both their native language (L1) and second language (L2) and self-reported their mental imagery vividness during each task. The findings revealed that participants exhibited higher creativity and more vivid mental imagery in their L1 compared to their L2, supporting the hypothesis that language context significantly impacts creative processes. Surprisingly, higher L2 proficiency was not associated with better creative performance in L2. When controlling for the effects of representational gesture use, I found that gestures in L1 were positively associated with divergent thinking, while gestures in L2 had a negative association. Furthermore, higher gesture rates during convergent thinking in both languages were associated with lower convergent thinking performance, particularly when imagery vividness was high. These findings highlight the complex interplay between gestures and imagery in bilingual creative processes and suggest that their role in supporting creative thought might vary with the language context. Overall, this dissertation provides a comprehensive examination of the role gestures play in various creative thinking processes across different gesture (spontaneous vs. encouraged) and speech (L1 vs. L2) contexts. The results offer valuable insights not only for multimodal language production research but also for the complex and dynamic nature of creativity. Most importantly, it inspires future venues for research that can have practical implications across various educational, artistic, and bilingual settings.