As part of the “Profiles in Evolutionary Moral Psychology” interview series, This View of Life had the opportunity to speak with Michael McCullough. Michael is Professor of Psychology and Director of the Evolution and Human Behavior Laboratory at the University of Miami, and he and Debra Lieberman were hosts of the 2013 annual meeting of the Human Behavior and Evolution Society in Miami. He’s currently researching and writing about revenge, forgiveness, gratitude, religion, and the evolution of human generosity.Professor McCullough is a highly influential researcher who takes an evolutionary perspective on moral emotions related to social exchange (such as forgiveness, revenge, and gratitude) as well as on religion and self-control. He has authored over 100 peer-reviewed articles and book chapters, and has authored or edited several books. His most recent book, Beyond Revenge: The Evolution of the Forgiveness Instinct, explores the origins of psychological mechanisms related to vengefulness and forgiveness. He argues that these two very different responses to harm are equally ‘instinctual’, and that the more we know about how evolution designed each of these emotions to work, the more control we’ll have to promote forgiveness over revenge. Also, he recently began blogging at www.Social-Science-Evolving.comHis interview provides some great insights into the influences and theoretical views that have driven his research.MICHAEL PRICE: What can evolutionary approaches tell us about human moral systems, that other approaches cannot tell us? That is, what unique and novel insights about morality does an evolutionary approach provide?MICHAEL MCCULLOUGH: For me, the unique value of an evolutionary approach to any feature of moral life—indeed, any behavioral or psychological process at all—is its insistence on clear and consilient thinking about biological design and about how the mind, as a biological organ, gets its information-processing work done. To think evolutionarily about a given feature of human behavior requires you, first off, to consider whether the trait in question is an adaptation in its own right or whether it is a by-product of some other adaptation. If you think it’s an adaptation, a variety of questions immediately begin to compete for your attention: What selection pressures favored the trait’s evolution by natural selection? Were those selection pressures a persistent feature of deep human history? What computational tasks would a naturally selected system for producing that behavior need to accomplish to have raised ancestral humans’ fitness? What cues might it have evolved to rely upon to regulate its operation? Does a phenomenon that we see in the laboratory reflect what the hypothesized adaptation in question evolved to do, or does the phenomenon reflect a “misfiring” in which the adaptation self-executes in response to environmental conditions that are only superficially similar to the conditions it evolved to care about?Anyone who has ever written up a paper on a research project that did not have an evolutionary foundation knows that you will eventually have to provide an apologia (probably in the paper’s introduction) for why your study was worth doing. That pressure to justify your paper’s existence is greatly reduced when you take an evolutionary angle because evolutionarily inspired questions about behavior emerge much more forcefully from first principles. They justify themselves.PRICE: The ordinary view in biology is that adaptations evolve primarily to promote individual fitness (survival and reproduction). Do you believe that this view is correct, with regard to the human biological adaptations that generate moral rules? Does this view imply that individuals moralize primarily to promote their own fitness interests (as opposed to promoting, e.g., group welfare)?MCCULLOUGH: I do believe the “ordinary view in biology” is correct. To the extent that moral sentiments or the systems that generate moral rules are biological adaptations, I think one is quite justified in assuming that they evolved by increasing individual organisms’ inclusive fitness—that is, either by boosting their bearers’ direct reproduction or by boosting the reproduction of the bearers’ genetic relatives. Even if we stipulated that some between-groups selection shaped these traits in humans (which I am perfectly willing to do), we still would not be licensed to conclude that humans’ groupish traits are “group adaptations” because group adaptations can only arise through clonal relatedness or the complete abolition of reproductive competition among group members, and (obviously) humans do not fulfill either of these conditions. To contend that we’re “like bees” or “like ants” just because we are highly cooperative and highly groupish can lead to the fuzzy thinking that often results from science by analogy.Instead, it’s perfectly defensible to think that we love our groups, support our groups, and are motivated to engage in between-group conflicts because of the direct and indirect fitness benefits of group life that redounded to individuals as our species was evolving. After all, the fact that infants love their caregivers and are motivated to maintain proximity to their caregivers does not imply that those parentish preferences and motivations are “parent-infant dyad” adaptations evolved due to selection between parent-infant dyads. Instead, we easily recognize them for what they are: Individual-level adaptations that caused ancestral infants to do better in the game of individual-level natural selection than did infants who lacked such parentish traits. By the same token, the fact that we like our own societies better than other people’s societies does not need to be thought of as evidence for adaptation at the group level—even if selection at the between-groups level helped to set the stage for their evolution.PRICE: What work by others on the evolution of morality (or just on morality in general) have you found most enlightening?MCCULLOUGH: Several books initially got me interested in applying evolutionary theory to my own work. These included Richard Wrangham’s Demonic Males, Frans de Waal’s Good Natured, Matt Ridley’s The Origins of Virtue, and Robert Wright’s The Evolution of God. I am very impressed with my colleague Deb Lieberman’s research on how individual differences in sexual morality (particularly, attitudes toward incest) emerge from individual differences in life experiences that calibrate the species-typical cognitive system that regulates incest avoidance. Michael Bang Petersen’s work on the evolved cognitive basis for individual differences in support for welfare policies is also very exciting. I also think that Peter DeScioli and Rob Kurzban have been doing highly creative work on the function of moral rules in helping people to choose sides in conflicts.PRICE: Which of your own publications are most relevant to an evolutionary understanding of morality? Which results or ideas from your work do you regard as most significant?MCCULLOUGH: I have two current favorites. I am still reasonably satisfied with my book Beyond Revenge: The Evolution of the Forgiveness Instinct, which came out in 2008. Also, I wrote (along with Rob Kurzban and Ben Tabak) an article-length update to the arguments I made in Beyond Revenge, and that paper came out in Behavioral and Brain Sciences in 2013. In these two works, we tried to explain how adaptations for revenge (or, if you prefer, punishment) and for forgiveness might have evolved in humans through natural selection. We also sketched out the information processing tasks that evolved systems for revenge and forgiveness would need to execute in order to do their jobs well.The BBS paper stimulated some extremely thoughtful commentaries. Revenge and punishment are very popular topics in evolutionary biology and evolutionary psychology right now, but there’s comparatively little theoretical work on human forgiveness, reconciliation, and other conflict remediation processes—even though there is some great work on these topics by animal behavior researchers. I’d love to see human forgiveness and reconciliation receive additional attention in the coming decade from evolutionarily oriented researchers.PRICE: What are the most important unsolved scientific puzzles in evolutionary moral psychology? MCCULLOUGH: I don’t think we’ve come very far in explaining how evolved systems for generosity (or cooperation, if you prefer) interact with other evolved cognitive systems to motivate generosity in the modern world. More generally, I am not quite satisfied with how much we know (especially relative to how much we think we know) about the evolutionary basis for people’s intuitive regard for the welfare of strangers in the modern world.I’m also curious about the functions of moral conscience and the ecological and life history factors that govern its development.Finally, I think we could make more progress in understanding how religion has become such a good vehicle for moralization, particularly over the past 10,000 years, with an eye toward addressing the “cui bono”? question: When we use a god or gods to prescribe or proscribe certain courses of action, which individuals within the society benefit? It’s easy enough to answer this question by making reference to some form of multi-level selection, but there’s an awful lot of detail that gets smoothed out of the picture when we’re willing to satisfy ourselves with that sort of master narrative. I think we need to give more attention to the competing agendas of individuals within societies to get a fuller picture of why and how people use religion to generate moral rules.LINKS:Check out Mike McCullough’s blog. Also, he’s on Twitter @McCullough_Mike.Here’s a link to the web site for the Evolution and Human Behavior Laboratory at the University of Miami and Mike’s webpage there with PDF’s of some of his papers.Listen to him on The Biology of Forgiveness, from NPR's To the Best of Our Knowledge (September 15, 2013).Here’s a link to his book Beyond Revenge: The Evolution of the Forgiveness Instinct at