Abstract
This chapter emphasizes the need to complement work investigating which brain regions support cognitive functions with work on how those brain regions support those functions. It starts with a bestcase scenario, one with unlimited resources to address the ‘what’ questions. But investigations of how questions may be even more important given that this bestcase scenario is unrealistic. It also describes some challenges to interpreting neuroimaging results below and suggests ways that mechanistic approaches may provide an important complement. In addition, although our chapter focuses on the promise of mechanistic accounts of frontal lobe function, there are important challenges in this domain as well. It describes some of these challenges and suggests ways that neuroimaging and other methods may provide an important complement.