 Another line of research is due to Joshua Greene and his colleagues (Greene et al. 2001, 2004, 2008; Greene 2008), who investigate the neural bases of consequentialist and deontological moral judgments (but see Kahane et al. 2015). Greene and his colleagues elicited the intuitions of subjects about a variety of trolley problems—cases that present a dilemma in which a trolley is racing towards five individuals, all of whom will be killed unless the trolley is instead diverted towards one individual—while inside an fMRI scanner. The researchers found that, when given cases in which the trolley is diverted by pulling a switch, most subjects agreed that diverting the trolley away from the five and towards the one person was the right action. When, instead, the case involved pushing a person off a bridge to land in front of and halt the trolley, subjects were less likely to judge that sacrificing the one person as morally permissible. In addition, Greene found that subjects who did judge it permissible to push the person took longer to arrive at their judgment, suggesting that they had to overcome conflicting intuitions to do so (but see McGuire et al. 2009)—a finding bolstered by the fact that when subjects considered pushing the person off the bridge, their brains revealed increased activity in areas associated with the aggregation and modulation of value signals (e.g., ventromedial prefrontal cortex and dorsolateral prefrontal cortex). Greene concludes that our aversion to pushing the person is due to an emotional response to the thought of causing physical harm to someone, while our willingness to pull the switch is due to the rational calculation that saving five people is preferable to letting five people die to spare one life. Greene and Singer use these findings as a basis for a debunking of deontological intuitions and a vindication of consequentialism, since the latter rests on intuitions which stem from a source we consider both generally reliable and appropriately used as the basis for moral reasoning. It should be noted, though, that this argument presupposes that emotional reactions are (at least in these cases) necessarily irrational or arational; philosophers who are unsympathetic to such a view of emotions need not follow Greene and Singer to their ultimate conclusions (Berker 2009; Greene 2014; Railton 2014).