What is the function of the human moral sense?

From the point of view of the rest of the animal kingdom, humans do two things which are decidedly odd. First, they cooperate in groups of non-relatives. Second, they are deeply concerned about what other members of their species are up to, even when others aren’t hurting (or helping) anyone. One line of my research program is aimed at shedding light on this second question. Why do humans label others actions—from theft to harm to selling kidneys—morally “wrong,” and why do we want others to be punished for such things. Departing from traditional approaches—including the one taken by Darwin himself—I and my collaborators (especially Peter DeScioli) have proposed a “bandwagoning” explanation of moral judgment. This view suggests that the human moral sense isn’t there to guide us towards helping others, but rather is guiding us to being on the same side that everyone else is taking when conflicts emerge. This controversial proposal is currently being tested in a series of lines of research.

Why do people form close friendships?

Like dolphins, chimpanzees, and a handful of other species, humans form lasting, non-kin-based social ties. Historically, the explanation for human friendships has been the idea of exchange. Based on early theories of reciprocity, the idea is that friends are useful to one another because they allow for gains in trade. You take me to the airport today, I’ll water your garden when you’re away next week. A problem for exchange theories is that one of the most important aspects of human friendships is that they are precisely not exchanges and we often don’t keep track of debts. If you make me dinner, and I leave a twenty dollar bill, I might well have just lost a friendship. A different explanation for friendships is that friends are allies, people who will support us when conflicts arise. The Alliance Model of friendship helps to explain various otherwise puzzling phenomena, such as friendship jealously. Why do we get angry when our close friends form new, close attachments to others? If the exchange model is right, then this is puzzling. But if friends are allies, then each of our friends’ friends are actually potential threats, forming closer alliance bonds than we have. Ongoing work is designed to distinguish between these two different explanations for human friendship.

Why is it so hard to persist on some kinds of tasks?

Some activities are so effortless, it feels like we can do them forever. Anyone who has played a marathon session of a favorite video game can testify to this. Other activities, however, are so effortful—mathematics, writing, and many others—that we have to force ourselves to persist. Why some tasks feel effortless and why some feel effortful remains a subject of debate. One idea is that there is a “reservoir” of “resources” in the head that gets “depleted” when one does effortful tasks, but not when one does effortless tasks. While there is substantial evidence weighing against this view, it is the predominant view among both the scholarly and lay community. An alternative explanation locates the answer in the notion of “opportunity costs.” When someone is doing mathematics, for example, the parts of the mind that are used for this task cannot be used for other tasks. The sensation of effort, then, can be understood—putting it somewhat roughly—as the mind’s way of getting you to switch from doing mathematics to one of the other tasks that one could be doing. If this is right, then the sensation of “effort” is evolution’s way of getting to switch to a new—possibly more rewarding—activity. Work in my lab is currently underway to test this idea.

What is the basic organization of the mind?

One area of debate in some areas of psychology surrounds the extent to which the mind is “modular,” consisting of a large number of specialized programs as opposed to a smaller number of less specialized programs. The evolutionary approach that animates my research suggests that the answer to this question is going to be that there are a very large number of very specialized components of the mind. Many specialized systems have already been described, such as those associated with the senses, certain kinds of memory systems, and even components designed around the social world. Work in my lab touches on this issue in various ways. Although the debate will not be settled in detail any time in the near future, projects in the lab address this issue from a number of different directions.