In my new book, Rightness as Fairness: A Moral and Political Theory, I argue that moral cognition and motivation--and by extension morality itself--emerges out of a problem of diachronic instrumental rationality (or rationality across time) that I call "the problem of possible future selves." In brief outline, the problem is that throughout our lives, we are capable of recognizing that we not only have interests in the present, but will have interests in the future--though, since the future has not yet come, we do not know for certain what those interests are. Thus, we have to somehow justify our actions to our future selves, despite not knowing precisely who our future self will actually be. I argue that morality itself--understood in terms of four principles of fairness--is the only rational solution to this problem, and that the moral theory that emerges from these foundations (Rightness as Fairness) satisfies seven principles of theory selection better than alternative moral theories.
In the book, I argue that there are a number of converging lines of evidence in favor of the proposition that morality is founded in the problem of possible future selves, and thus, that (contrary to much of moral philosophy) morality and prudence are continuous rather than discontinuous (or distinct). [Note: references to the findings summarized below are in Rightness as Fairness].
First, it turns out that one of the general cognitive capacities that underlies the problem of possible future selves--the capacity of mental-time travel (which consists in the ability to imaginatively occupy one's own different possible pasts and futures)--varies in human and animal species in more or less direct proportion to moral responsibility. Normal human adults have robust mental time-travel capacities. In contrast, children and adolescents--who we say colloquially are "unable to appreciate the consequences of their actions"--have reduced/still developing capacities to imagine and care about their future. Further, human psychopaths--who are notoriously unable to "perceive moral reasons"--appear to lack robust mental time-travel capacities (and lack brain development in areas thought to be responsible for these capacities. Nonhuman animals also appear to lack mental time-travel capacities. In the book, I also argue that our capacities of mental time-travel underlie our capacity of perspective-taking (i.e. seeing others' perspectives and interests as possibly our own).
Second, it turns out in various studies that mental time travel capacities coupled with caring about one's future are strongly implicated in both moral and prudential behavior. On the one hand, some of the strongest individual-level predictors of criminally delinquent behavior are (a) impulsivity, and (b) lack of concern for one's future. On the other hand, studies where people are actively primed to think about their future--such as by interacting with an aged virtual reality version of themselves--have found improved moral and prudential behavior (viz. a tendency to save more money and lesser willingness to cheat or endorse selling stolen property).
It turns out a new study further supports this picture of moral and prudential deliberation! The study, in Scientific Advances, found via transcranial magnetic stimulation (TMS) that a single brain-region--the temporoparietal junction (TPJ)--underlies our capacity to imagine our future selves and place ourselves "in each other's shoes." Further, TMS was used to inhibit activity in that brain region...and the results were these:
Subjects with an inhibited TPJ were less likely to share the money and were more likely to take the money up front rather than delay gratification and wait for a larger prize. They were also less able take on the perspective of the avatar, which makes sense, says Christian Ruff, a co-author of the paper and an economist at the University of Zurich. “The function of perspective-taking is essential to both of these tasks,” he says, in terms of both “thinking how someone else would feel if you give them money and also how you yourself in the future would feel with that money.”
The findings suggest that the TPJ plays an important role in perspective-taking, which Ruff describes as “a very basic social mechanism” that is essential not only for helping us figure out what other people may be thinking and feeling during social interactions but also in self-control, as we weigh the needs and desires of our current self against the needs and desires of our imagined future self.
Beyond addiction, self-control and our ability to delay gratification is relevant to almost every decision we make in life, from finishing school to exercising regularly to saving for retirement, which is why Ruff considers understanding self-control central to improving health and well-being.
Joseph Kable, a psychologist at the University of Pennsylvania who was not involved in the study, finds the results interesting and surprising. “Most of the research on this brain area which they are inhibiting has suggested that it plays a role in social decisions, in perspective-taking,” Kable says. “I don't think many people would have predicted that it would have a role in temporal dilemmas, where you face this conflict between a smaller immediate reward and a larger reward that you can only get if you wait until the future.”
The researchers might not have predicted that the same brain regions would underlie perspective-taking (viz. moral deliberation) and temporal dilemmas (viz. prudence)...but Rightness as Fairness did. :)