magazine issue 8 2015 / Issue 27

Why do we so often ignore the influence of situations on behavior?

• written by Joe Moran
• edited by Laysee Ong

But what exactly was going on? Why would people who knew that a position had been given via a coin-flip confidently ignore that information and believe that the writers held such a socially undesirable position in their hearts? As previously mentioned, one possible reason for this error—a mechanism for it—is that people, when they encounter other people, are engaged in constant prediction about what those others will do next. Because these predictions are so adaptive, necessary, and automatic it might simply be second nature to have a well-traveled causal highway that links behavior and intentions—after all, if we know someone’s intentions, we can do a good job of figuring out what action they will take next—instead of thinking about the things in the environment that could also have caused people’s behaviors. The cognitive process that allows us to figure out intentions has been referred to as mentalizing or theory of mind, terms used almost interchangeably in the literature (Baron-Cohen, Leslie, and Frith, 1985). When we look to the cognitive neuroscience of mentalizing, we see that almost twenty years of research has converged on the idea that a particular set of brain regions is responsible for representing others’mental states and intentions. In one of the first functional imaging investigations of mentalizing (Fletcher et al., 1995), participants read short stories and answered questions about those stories that relied either on the understanding of mental states or of physical states. Fletcher and colleagues reasoned that these two kinds of stories would be broadly identical except that mental stories necessitate mentalizing, and that contrasting the two story types might reveal activity in brain regions that were specially engaged by this process, and not by other processes that are common to reading stories in general. What they found, to their surprise, was that a single region of the medial frontal gyrus was more active when participants read mental stories than when they read physical stories. This region of the brain is part of the prefrontal cortex (on its medial, or central surface), and is found directly behind the forehead, between and just above the eyes. Until Fletcher and colleague’s seminal work, little attention had been paid to this region’s function—a brain area which has undergone more development than almost any other in evolutionary terms, being twice as large in humans than in any of our great ape relatives (Semendeferi et al., 2001)—but since this original paper, hundreds of investigations have revealed a role for the medial prefrontal cortex in tasks that involve mentalizing or other related social-cognitive phenomena such as deception, moral judgments, and impression formation (Wagner et al., 2012).

The medial prefrontal cortex also forms a central component of the brain’s default mode network (Raichle et al. 2001; Andrews-Hanna et al., 2010), so called because this network is most metabolically active when we are at rest, unengaged in goal-directed tasks like memory or attention (Shulman et al., 1997). Because of this overlap between the so-called resting state and mentalizing, one theory that naturally arises is that much of what is charitably referred to as ‘rest’by cognitive neuroscientists may in fact be simulation of our social interactions, internally generated thoughts about our own lives, and so on (Andrews-Hanna et al., 2010b; Tamir and Mitchell, 2010; Whitfield-Gabrieli et al., 2011; Moran, Kelley and Heatherton, 2013). It is indeed likely that the sorts of ongoing mental predictions about how John will react to your news, or whether Sophie will like Jack, are those that, in the absence of a task when we are lying inside an MRI scanner (or in our real, daily lives) are the ones that we will default to considering (Wicker et al., 2003).