Stanovich and West (2008) explored if measures of cognitive ability ignored some important aspects of thinking itself, namely that cognitive ability alone is not enough to generally prevent biased thinking. In this thesis a series of decision making (DM) tasks is tested to see if emotion regulation (ER) is a factor for the decision process and therefore should be a measured in decision making competence. A set of DM tasks was compiled involving both affective and cognitive dimensions. 400 participants completed an online web-survey. The results showed that ER ability was significantly associated with performance in various DM tasks that involved both heuristic and biased thinking. These findings suggest that ER can be a factor in decision making competence.