In this study two experiments were conducted to identify the optimal conditions for divergent and convergent thinking. Two different thinking styles were considered as two different types of creativity: divergent thinking (measured by Alternative Used Task; Guilford, 1967 ) and convergent thinking (measured by Remote Associate Task; Mednick, 1962 ). In the first experiment we studied whether individual performance in divergent and convergent thinking tasks can be predicted by the individual spontaneous eye blink rate (EBR), a clinical marker of dopaminergic functioning. The results showed a negative correlation between convergent thinking and EBR-dopamine levels, and performance on divergent thinking test followed an invert U-shaped relation with an individual’s dopamine level. In this experiment performance of the individual with moderate level of eye blink rate was better and higher than individuals with low and high EBR. These results were considered as the basic idea to run the second experiment as a mood induction experiment. Mental imaginary procedure was used for inducing either positive or negative mood. In this experiment two groups of subjects participated in a mood induction (either positive or negative) experiment. Individual's eye blink rate was recorded before and after mood induction. Performance of all the subjects in two set of divergent thinking tasks were measured before and after mood induction. Results of this experiment show positive mood, when compared to negative mood, enhanced creative performance on divergent thinking test. Positive mood significantly improved performance in divergent thinking: flexibility of people with low dopamine level. But there is a different scenario for people with medium (or high) level of dopamine, as the benefit of positive mood was very small and not significant at all for them. We conclude that impact of positive mood on the performance in divergent thinking depends on an individual’s
