self has essentially no meaning except in distinction to some other, and so the relevant question becomes where to draw the borderline between the two. In social psychology, studies of group identity have suggested that sometimes the notion of self extends beyond that of the individual. Here, we suggest the reverse: in one specific but important way—namely across time—the notion of self is considerably narrower than the individual.
That is Julian Jamison and Jon Wegener in a new behavioral economics paper.
To understand decisions made across time, economists often model individuals and their future selves as separate persons. Just a modeling convenience? Maybe not. Jamison and Wegener argue that brain systems and decision processses work exactly that way.