Loewenstein and Lerner divide emotions during decision-making into two types: those anticipating future emotions and those immediately experienced while deliberating and deciding. Damasio formulated the somatic marker hypothesis (SMH), that proposes a mechanism by which emotional processes can guide (or bias) behavior, particularly decision-making. Pfister and Böhm believe that "the issue of rationality should be based on the validity of emotional evaluations rather than on formal coherence."