This study combines psychological fundamentals with Institutional Economics in order to understand relevant aspects of consumers' decision making and firms' behaviors in pursuit of benefiting from that knowledge. This study emphasizes that psychological fundamentals can offer more analytical insights to Institutional Economics. The psychological basics applied to an institutional analysis of consumers' decision making are divided in two parts. One relies on the importance of instincts as motivation to consume, the other is based on cognition and vicarious observation as central aspects of consumers' learning processes. A central argument of this study is illustrated by two cases: one explores how functional yogurt was introduced to Brazilian consumers and the other investigates the transference of objects of consumption from comic books to movies.