Structural studies of creativity measured by divergent thinking

In this chapter, we would like to discuss structural studies on brain imaging to evaluate creativity as measured by divergent thinking (CMDT). Human intellectual abilities have been shown to be strongly associated with structural volumes and microstructural properties of the brain using structural magnetic resonance imaging (sMRI) techniques (Jung & Haier, 2007; Posthuma et al., 2003). More specifically, these studies used T1-weighted high-resolution structural images to evaluate regional gray matter (GM) and white matter (WM) volumes (rGMV and rWMV, respectively) via voxel-based morphometry (VBM), and to evaluate cortical thickness and the surface area of the brain. These studies also used diffusion tensor imaging (DTI) to evaluate fractional anisotropy (FA) and mean diffusivity (MD) of the brain. A number of recent studies in the field have used similar methods to identify correlations between properties of brain structures and CMDT. In this chapter, these CMDT studies are reviewed, and their methodologies and implications described. Creativity is conventionally measured using divergent thinking tests, in which the subject is instructed to generate as many ideas or uses as possible in response to certain stimuli (e.g., a brick). These tests include not only verbal divergent thinking tests but also figural divergent thinking tests, in which the subject is presented with a picture and is required to respond with their own variations of drawings. Divergent thinking has been proposed as a key aspect of creativity (Guilford, 1967) and is currently the dominant measure of creativity in the field. Scores of CMDT have a stronger relationship with creative achievement than scores of intelligence tests (for a meta-analysis, see Kim, 2008). Therefore, among the many aspects and components of creativity, CMDT studies will be the focus of this chapter. The chapter will begin by offering a brief review of some methodological approaches to structural studies of the brain before delving into a discussion of their associations with CMDT. VBM and Cortical Thickness Analysis VBM is a structural processing technique using brain MRI that involves a voxel-wise correlation between rGMV or rWMV and any factor of interest, such as age and cognitive function (Ashburner & Friston, 2000). The individual structural images are segmented into GM, WM, and cerebrospinal fluid.