Biological Mechanisms in Creativity and Flow
Sammanfattning: What would the world and our lives look like, if creativity had not evolved? Defined as the ability to have ideas and produce artifacts that are at the same time novel and meaningful, creativity is arguably one of the faculties that has given the human species adaptive ability beyond any other organism. The goal of this thesis was to elucidate some of the biological mechanisms that enable creative thinking. Four studies, based on three different methodologies are presented. Study I was performed in order to investigate the putative relationship between creative thinking and dopaminergic function. Scores on divergent thinking tests were correlated with regional D2 receptor densities, as measured by PET. The results showed a negative correlation between divergent thinking and D2 density in the thalamus, controlling for age and general cognitive ability. Decreased D2 receptor densities in the thalamus may be associated with lower thalamic gating thresholds, i.e. an increased thalamocortical information flow, which could facilitate the generative processes that underlie creativity. This is the first study to indicate such a mechanism. This mechanism may also provide a link between creativity and mental illness. Previous research on the flow experience has shown that flow states facilitate creative thinking. In study II, physiological processes associated with the flow experience were studied. Professional classical pianists were asked to play a musical piece five times and rate state flow after each performance. The arterial pulse pressure, respiration, head movements, and activity from the corrugator supercilii and zygomaticus major facial muscles were measured for each performance. A significant relation was found between flow and heart period, blood pressure, heart rate variability, activity of the zygomaticus major muscle, and respiratory depth. This is the first study to show that subjectively experienced flow is reflected in biological processes. The findings are discussed in relation to a conception of flow as a state of effortless attention. Previous research suggests that the rostral dorsal premotor regions (PMDr), might be particularly involved in the generation of melodic structures; whereas the pre-supplementary motor area (pre-SMA) may contribute more to the generation of rhythmic sequences. Study III tests this hypothesis. Brain activity during improvisation in professional pianists was measured using fMRI. The results partly confirmed the hypothesis: Melodic improvisation loaded more on the PMDr than did rhythmic improvisation; activity in the pre-SMA was related to rhythmic improvisation, but also to melodic improvisation. The results also indicate that perception, performance, and free generation share neural mechanisms. Study IV presents an fMRI paradigm aimed at comparing the neural underpinnings of pseudo-random free generation and musical improvisation. Professional classical pianists performed improvisation of melodies, pseudo-random key presses and sight-reading, using either two, six or twelve keys on a piano keyboard. The results showed that musical creativity originates from similar cortical networks as other forms of free generation, and that adding a musical context does not engage additional brain regions. Pseudo-random generation, however, was accompanied by higher activity than improvisation in several fronto-parietal regions, which may be related to the high complexity of this task and the musical expertise of the subjects.
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