Give your ideas a hand: the role of iconic hand gestures in enhancing divergent creative thinking.

Hand gestures play an integral role in multimodal language and communication. Even though the self-oriented functions of gestures, such as activating a speaker's lexicon and maintaining visuospatial imagery, have been emphasized, gestures' functions in creative thinking are not well-established. In the current study, we investigated the role of iconic gestures in verbal divergent thinking-a creative thinking process related to generating many novel ideas. Based on previous findings, we hypothesized that iconic gesture use would facilitate divergent thinking in young adults, especially those with high mental imagery skills. Participants performed Guildford's Alternative Uses Task in a gesture-spontaneous and in a gesture-encouraged condition. We measured fluency (number of ideas), originality (uniqueness of ideas), flexibility (number of idea categories), and elaboration (number of details) in divergent thinking. The results showed that producing iconic gestures in the gesture-encouraged condition positively predicted fluency, originality, and elaboration. In the gesture-spontaneous condition, producing iconic gestures also positively predicted elaboration but negatively predicted flexibility. Mental imagery skills did not interact with the effects of gestures on divergent thinking. These results suggest that iconic gestures are a promising candidate for enhancing almost all aspects of divergent thinking. Overall, the current study adds a new dimension to the self-oriented function of iconic gestures, that is, their contribution to creative thinking.

The creative interplay between hand gestures, convergent thinking, and mental imagery.

Using hand gestures benefits children's divergent thinking and enhances verbal improvisation in adults. In the present study, we asked whether gestures were also associated with convergent thinking by activating individuals' verbal lexicon and maintaining their visuospatial imagery. We tested young adults on verbal and visual convergent thinking, controlling for their mental imagery skills. Results showed that gestures and mental imagery skills play a role in verbal but not visual convergent thinking. Regardless of whether gestures were spontaneous or encouraged, we found a negative association between overall gesture frequency and verbal convergent thinking or individuals with low mental imagery, and a positive association for individuals with high mental imagery. Representational gestures benefited verbal convergent thinking for everyone except those who had low mental imagery and no experience with the task. Performing beat gestures hampered verbal convergent thinking in people with lower mental imagery capacity and helped those who had high mental imagery and previous experience with the task. We also found that gesturing can benefit people with lower verbal abilities on verbal convergent thinking, however, high spatial imagery abilities were required for gestures to boost verbal convergent thinking. The current study adds a new dimension to both the embodied creativity literature and the kaleidoscope of individual differences in gesture research.

The cost of changing language context: The language-dependent recall of fictional stories.

Language-dependent recall refers to the language-specific retrieval of memories in which the retrieval success depends on the match between the languages of encoding and retrieval. The present study investigated language-dependent recall in terms of memory accuracy, false memory, and episodic memory characteristics in the free recall of fictional stories. We also asked how language-dependent memories were influenced by language proficiency and visual imagery. One hundred and thirty-seven native Turkish (L1) speakers who were second-language learners of English (L2) were divided into four groups in which they read fictional stories and then recalled them: (1) Turkish reading-Turkish recall, (2) English reading-English recall, (3) English reading-Turkish recall, (4) Turkish reading-English recall. Regardless of the match between L1 or L2, accuracy was higher when participants read and recalled the stories in the same language than when they did it in different languages, showing the language-dependent recall effect. Notably, the effect of match or mismatch between encoding and retrieval languages on accuracy did not depend on L2 proficiency and visual imagery. In addition, false memories were salient, particularly for participants who read the stories in L2 but retrieved them in L1. Overall, our findings suggest that accuracy-oriented memory research provides a comprehensive investigation of language-dependent recall, addressing the links of language-dependent memories with accuracy, false memory, and episodic memory characteristics.

Ageing, working memory, and mental imagery: Understanding gestural communication in younger and older adults.

Ageing has effects both on language and gestural communication skills. Although gesture use is similar between younger and older adults, the use of representational gestures (e.g., drawing a line with fingers on the air to indicate a road) decreases with age. This study investigates whether this change in the production of representational gestures is related to individuals' working memory and/or mental imagery skills. We used three gesture tasks (daily activity description, story completion, and address description) to obtain spontaneous co-speech gestures from younger and older individuals (N = 60). Participants also completed the Corsi working memory task and a mental imagery task. Results showed that although the two age groups' overall gesture frequencies were similar across the three tasks, the younger adults used relatively higher proportions of representational gestures than the older adults only in the address description task. Regardless of age, the mental imagery but not working memory score was associated with the use of representational gestures only in this task. However, the use of spatial words in the address description task did not differ between the two age groups. The mental imagery or working memory scores did not associate with the spatial word use. These findings suggest that mental imagery can play a role in gesture production. Gesture and speech production might have separate timelines in terms of being affected by the ageing process, particularly for spatial content.

Cathodal tDCS stimulation of left anterior temporal lobe eliminates cross-category color discrimination response time advantage.

The linguistic category-advantage in color perception refers to better discrimination performance for stimuli that belong to different categories (e.g., green vs. blue) than equidistant stimuli from the same category (e.g., blue). Despite the robust nature of category-advantage in color perception, the related cognitive and neural mechanisms are not fully understood. Some views attribute this effect to early alteration of visual processing of color while others attribute it to post-perceptual conceptual processing. The current study investigated the causal role of the left anterior temporal lobe (ATL), as a post-perceptual semantic hub, in categorical color perception. We modulated the activity of the left ATL via cathodal tDCS or sham stimulation (within-subject) while participants were discriminating between successive presentations of color patches. Without stimulation, we found a category-advantage effect in both accuracy and response times. The inhibition of left ATL eliminated the category-advantage effect in terms of RTs but not accuracies. Our results point at the causal role of ATL in categorical color perception and provide indirect support for a post-perceptual processing account of this robust phenomenon.