EEG complexity and performance measures of creative thinking

The electroencephalogram (EEG) was used because of its dimensional complexi ty to establish a differentiation of divergent versus convergent thought, c onsidered fundamental modes of cortical processing. In 28 men, the EEG was recorded while solving tasks of divergent and convergent thinking and durin g mental relaxation. The EEG during divergent thought was compared between subjects achieving high versus low performance scores on this type of task. The dimensional complexity of the EEG was greater during divergent thinkin g than during convergent thinking. While solving tasks of divergent thinkin g, subjects with high performance scores had a lower EEG dimension than did subjects with low scores, in particular over frontal cortical areas. The c hanges were not reflected in single frequency bands of conventional EEG ana lysis. Based on Hebb's view of neuron assemblies as functional processing u nits, the higher EEG complexity during divergent than convergent thinking c ould be the result of the concurrent activation of a greater number of inde pendently oscillating processing units.