This week’s discussion of the introductory chapter, “Evolutionary Ethics and Christian Morality: Surveying the Issues” by Jeffrey Schloss (in van Huyssteen. 2003. Evolutionary Ethics) focuses on two large camps of scholars from the fields of evolutionary biology and theology with respect the origins of ethics and Christian morality.  Philosophers of science and religion are found on both sides of the issues.  We noted at the beginning of our discussion that neither camp represents a monolithic view of the key issues in this relatively modern dispute – a debate sparked most recently by the publication of Darwin’s (1859) On the Origin of Species.  As noted by Schloss, “many Christians” view evolutionary theory as having the goal of destroying “theological and moral belief.”  Schloss argues (with appropriate references) that the two camps “vary wildly” on how to properly engage in a meaningful discussion of the issues.  Schloss’ paper describes this history with the goal of analyzing the debate in such a way that it can lead to a more constructive discussion of what the issues are.  Thus, he hopes to provide a framework for understanding and possibly reaching a consensus on the “real” issues. His paper sets a tone for the essays that follow in this volume, but are not the within the province of this blog.


The discussion began with Lucas addressing some of the terminology in the paper as it seems overburdened with the jargon of the several disciplines.  Agency was briefly defined as free will but not in the classical sense. Lucas doubts that the classical conception exists any longer.  Also, agency was noted to include the two major ethical categories, means and ends.  Agency was briefly defined again as the free will of a non-philosophical determinist (see Blog 6.1).


Discussion then moved to issues outlined by Schloss (pp. 4-5) in the section General Considerations. Wright (p. 5, paragraph 1) is especially concerned that current scholars with sociobiological approaches have taken positions that can only be described as a “loss of agency” at the organismal and mental levels.  Schloss argues here that the significance of their argument “is not the determinism but the reductive reconceptualization from organism as agent to organism as instrument.”


Some members of both major camps are deeply concerned that the agency of organisms (man) has been cast aside. Lucas phrased the issue in a metaphor of a freight train: are we the cars or the engine; are we the pulled or the puller.  Lucas views the loss of agency as one of the major issues in the disputes between scholars engaged evolutionary ethics and Christian morality debate.  Examples of such evolutionary reductionism are illustrated in the writings of sociobiologists Wilson and Dawkins (Schloss, p. 5).


Subsequently, we talked about the relationship between principles that may be objective or subjective goals – in and of themselves – and habits or categories of behavior that lead to other goals.  We tended to use “ethics” to refer to the former, but note that usage is inconsistent and even the division into those two categories represents certain philosophical commitments. The discussion led to a listing of several ethical categories, definitions and perspectives, e.g., material realism, ethical realism, natural ethics (Aristotle, Aquinas), empirical ethics and constructivism. Each of these categories was defined.



FIG. 1: (Arrows indicate path of inference)


IS                        ——-?———à           OUGHT

Descriptive                                               Prescriptive

Explanatory          ß—-?———–            Normative


(We note that modern biologists tend reject the bottom arrow, at least insofar as they are doing biology.)



Further discussion led to the construction of the diagram in Figure 1 to clarify the “is/ought” relationship in ethical thinking.  We agreed: it is not clear that a descriptive or explanatory “truth” is a valid ethical principle that necessarily leads to a prescriptive ought. (This move is often referred to as the naturalistic fallacy).  We briefly considered this “is/ought” relationship and noted, for example, the relationship between descriptions of evolutionary forces promoting male promiscuity and prescriptive judgments about male promiscuity in humans.  Is this the kind of ethical thinking to which one ought to subscribe?  Lucas noted that Dawkins, Harris and Monod reject the idea that oughts exists in evolutionary ethics.  However, he also noted that the authors then beg the question by advocating for behavior without justifying their preferences.  Following this discussion, the group was polled and nearly all agreed that they are material realists (thinking that physical matter exists objectively, independent of observers).  We pondered the validity of ethical realism (the idea that some things are objectively better than others, independent of the preference of individuals) and posed the following questions.  If there is a real ethics, can we deduce what it is?  Is it empirically based? And how do ethical behaviors relate to the theory of ethical realism?



In discussing Fig. 1 we talked about a number of historical issues.

1) We have a tendency to describe behaviors as either good or bad, that is, we speak with an “ought” component.

2) Historically, Plato spoke of arriving at knowledge of both IS and OUGHT deductively, by reasoning down from known universals.  Platonic Realism has been replaced by (Ocham’s) Nominalism and (Bacon’s) Empiricism, through which we reason up from particular observations to general rules when we speak of knowledge of what IS in science.

3) Aristotle and Thomas Aquinas argued that we could also derive knowledge of OUGHT by reasoning up from particulars, but this has not been as broadly accepted.

4) Aquinas’ inductive ethics (Natural Law), can be contrasted with Augustine’s distinction between what may be known by looking externally (the natural world) and what may be known by looking internally (ethics).  Christian ethics tends to be either Thomistic or Augustinian.

5) Hume and Bacon expressed severe skepticism about the ability to reason about causes, agents, and ethics in the same way one argues about physical reality.



We talked briefly about questions of how altruism and ethical behavior relate to questions of K versus r life history strategies (See Meeting 5.4). From a scientific perspective, we felt that one can only describe how ethical behaviors came to be; we cannot state what they ought to be.  Even for the descriptive questions, we felt that science can only offer very tentative answers at this time.


Lucas attempted to clarify how one’s ethical thinking fits into biological models using equations.  The equations highlighted interesting areas of miscommunication, though in the end we had mixed feelings about their utility.




X:  There is an adapted/evolved component to ethical behavior in the form of predispositions, principles, or behavioral modules.  (reciprocal altruism…)


Q:  If we assume Ethical Realism (ethics exist independent of their observers) and if we further assume some faculty whereby humans can perceive ethics and if we further assume that they have an ability to change their behavior as a function of what they perceive, this is the component of behavior determined by real ethics.  Q may equal 0.


T:  Environmental effects (excluding responses to real ethics, which could be environmental if they exist).  In general members considered this to be physical environment, but that is not necessary to the model.


Can behavior be sufficiently described by F(x, q, t)?  Can it be described by F(x,t)?  Are there other components and how do these components relate?


We discussed whether and how one might empirically investigate the adapted element of ethic principles and behaviors.


We discussed the difference between two types of mindsets: those that speak of human behavioral norms and preferences as ethics, as an end (either identifying the proper ends of things or choosing to pursue a course), and those that see the norms and preferences as a means to some other end (reproduction, success, happiness,…).  Some of us leaned toward the former and worried the latter reduced or demeaned ethics in some way.  Some leaned toward the latter and felt natural selection (by means and to the end of survival and reproduction) provided a compelling and sufficient explanation of “ethical” behavior.


– Malcolm Levin              

This week we discussed the relationship between altruism and homosexuality, focusing on humans. As with all of our sessions, we began with a discussion of definitions. This was even more important than usual due to the topical and slightly controversial nature of today’s subject.

Sex – dimorphism in sexually reproducing species.  In animals, maleness is assigned to the sex with the reduced gamete – sperm.  Femaleness is assigned to the sex with the larger gamete – egg.  Sex is biological and can be determined empirically: Male/Female.

Gender – socially assigned role usually (not always) correlated with sex but culture dependent. Comes with social expectations of clothing, behavior…  Gender roles can be observed empirically but differ between cultures: Masculine, Feminine.  Note that Samoa and many other cultures have additional genders.  [Gender identity has to do with an individual’s self assigned role.]

Sexual Preference – the sex which an individual is more likely to engage in sexual behavior with, given a choice. This can change over time (sometimes quite quickly), and desire and behavior may not match.


Sexual Orientation – deals with stable and long-term sexual preferences in humans.  May or may not align with sex and gender.  Orientation has empirical and psychological elements:  Androphilia (attraction to men), Gynephilia (attraction to women).  [Homosexual, Heterosexual, Straight, Gay, Lesbian all connote some aspect of orientation relative to sex.] There are correlates in nonhuman animals, but the term “homosexual,” due to its connotations with human society, should not be used to describe nonhuman animals.

Sexual Behavior – empirically observable actions.

Homosexuality in humans is prevalent and has a large heritable component.  From a naïve evolutionary perspective, this presents a puzzle as homosexuals are estimated to have ~20% the reproductive success of their straight counterparts (NB: human homosexuality has been studied much more in males than in females). A major question—and the one on which we focused today—is how this orientation (and associated behavior) could become widespread in light of fitness concerns.  As an extreme example of a trait that appears stable in spite of apparently decreased personal fitness, it may shed light on questions of biological altruism.


In non-human animals, there are a variety of same-sex sexual behaviors, including long-term pair bonds, and also a variety of explanations for these behaviors. These explanations are generally divided into two categories: those that describe same-sex sexual behavior as adaptive and those that describe it as non-adaptive. Common non-adaptive explanations for same-sex sexual behavior include:

Mistaken Identity, where males have a weak ability to discriminate between members of the two sexes and frequently attempt to copulate with other males.

Prison Effect, where individuals will engage in sexual activities with members of the same sex when deprived of the opposite sex. This is well documented in several animals, including humans.

Infection.  Several insect species have parasites that affect sex ratio, reproduction, and mating behavior.  We were not aware of particular examples causing same-sex sexual behavior, but it has been posited.


Most current work has looked for adaptive explanations for same-sex behavior.  We discussed several of these.

Practice – Immature individuals may practice sexual activities with members of the same sex, as occurs in fruit flies, preparing them for later reproductive behavior.

Dominance – Same-sex sexual behavior is often used to reinforce dominance hierarchies independent of fertilization/reproduction attempts.

Heterozygote advantage – Species that have paired chromosomes carry two copies of almost all genes.  In some cases, having one mutated gene (and one normal) results in higher than normal fitness, even though two mutated genes causes lower than normal fitness.  It has been suggested that homosexuality results from homozygosity (two copies) of a gene that provides a heterozygote (one copy) advantage

Sexually antagonistic selection is when a gene increases fitness in one sex and decreases it in the other, so genes that cause same-sex behavior in one sex may increase fitness in the other sex.

Social glue – This theory suggests that sexual behavior can decrease conflict and improve social bonds between members of the same sex.  This has been well studied in dolphins, birds, and non-human primates, and has been extended to humans by suggesting that societies with some gender non-conforming individuals are more cohesive.

Kin Selection – Currently the most popular explanation for human homosexuality is kin selection. Homosexuals may forgo personal reproduction and instead invest resources in their siblings and siblings’ offspring, increasing their inclusive fitness. The theory predicts that homosexuals are more generous aunts and uncles than heterosexuals.


We examined a test of the Kin Selection prediction by reading a psychological paper on Samoan fa’afafine. Fa’afafine are a third gender distinct from “men” and “women”. They are physiologically male individuals who take on female gender roles.  They are usually attracted to men (orientation), typically display effeminate characteristics (gender), and are widely accepted by traditional Samoan society.

Vasey and Vanderlaan (2012) investigated fa’afafine to see whether their self reported inclination to help others matched the predictions of kin selection/ inclusive fitness.  They found that fa’afafine are more generous to children than other islanders on average, but disproportionately generous to nephew and nieces.  The effect held, even in comparison with single “men”.  The observation was consistent with the idea that inclusive fitness might support the prevalence of the trait.  It’s unclear, however, whether this aspect alone could compensate for the direct fitness costs.

Interestingly, the difference between straight and gay men’s avuncular (avuncular = of uncles) inclinations is not found in the United States.  The standard explanation for this is that American families are not as close-knit and gay men are more likely to be ostracized.

We ended our discussion speculating on celibate abstinence among monks, nuns, and priests in medieval Europe.  While not a direct parallel, it also reflects a large class of people taken out of the gene pool.  It is hard to assess the relative causes for this, though clearly there were voluntary and involuntary, pious and pragmatic elements.  From one group selection standpoint, celibacy may have served as a method of minimizing nepotism.  Celibate clerics would be more likely to favor the group or the group’s ideology, not being tempted to focus on their own spouse and progeny.   It may also represent a form of “brood reduction.”  Since childhood mortality rates were high, families wanted to have lots of children, but didn’t have the resources to provision lots of children. In landed families, the first son might be raised as the designated heir, with younger sons held in reserve in case they were needed.  Once the heir had survived the high mortality rates of childhood, younger sons would be “given away” to the Church. Similarly, one or two daughters may be useful for forming alliances, but more may be expensive to maintain or provide a dowry for.  They may be sent to a convent in their early teens.  This provided parents with a way to limit the size of the family, provided children with an occupation and support.  It also the opened possibilities for social and political connections through the Church, especially for the mercantile and upper classes.

-Kea Skeate

Human Altruism and Social Structure

            This week we discussed the article Strong Reciprocity and the Roots of Human Morality by Gintis et al 2008 in relation to the evolution of human altruism and morality. The authors of this work set up a dichotomy early in the paper between two opposing camps. In the first camp are those who view human morality as “enlightened self-interest.” According to this view, human morality evolved under individual selection in small closely related hunter-gather groups in which altruism was favored because nearly all interactions would be among close kin rather than strangers. However, in the modern day, humans interact much more commonly with strangers and human morality is a maladaptive left over from our hunter-gatherer days. The second camp asserts that human altruism and morality evolved as a result of group selection. The idea dates back to Darwin who suggested in his book The Decent of Man that, under natural selection, “tribes” with a higher proportion of altruists would fare better than those lacking and thus morality would be favored. To help explain why this is the view they favor, the authors introduce their concept of strong reciprocity which they define as “a propensity, in the context of a shared social task, to cooperate with others similarly disposed, even at personal cost, and a willingness to punish those who violate cooperative norms, even when punishing is personally costly.” In their view, morality is an innate trait that is favored by group selection and lacks selfishness. While discussing the paper, our group felt that the authors characterized the biological literature on human morality, altruism and kin selection and seemed not to understand the genetic based views of Hamilton and Dawkins. The authors seemed to feel that group selection is somehow less selfish than kin selection and ignored the parallels between the two schools of thought and the fact that group selection can act synergistically with kin selection if the group in question happens to be made up of closely related kin. Overall, the authors appear to have been trying to make a case for why “true altruism” should be favored.

We also discussed the Ultimatum Game from game theory in relation to human morality. In the basic form of the Ultimatum Game there are two players, A and B. A has a set amount of money, say $100 that it must share with B, so A proposes a split to B which B can either accept or reject. If B accepts the split then both players get to keep their respective amounts, however, if B rejects the split then neither player gets to keep any money. The rational strategy of this game would be for B to accept any offer from A because receiving something is better than nothing, likewise, A should offer B a meager portion the money (say $1) in order to maximize their own profit. However, in experimental trials B subjects tend to reject offers from A that they perceive as unfair even though doing so results in neither player receiving any money, and show emotional upset when presented with an unfair offer. The level that is perceived to be fair varies from culture to culture but the results appear to be similar across cultures. Likewise, A subjects often offer rather high splits that are close to fairness (say 50%) initially despite this not being the rational choice. However, in repeated games (with the same pool of participants but different pairs each time) A subjects gradually begin to offer less and B subjects gradually begin to accept less. However, if B is given the opportunity to spend money to punish A for being unfair the results change. A quickly learns to offer B a fair deal to avoid punishment. This strategy however is also not rational; a rational B can only lose money by spending it to punish individuals with whom he/she will not be paired in the future. Yet in experiments, B subjects often choose to punish A. Similar results are also observed in the opposite situation where B can pay a cost to reward A for acting fairly, despite it being irrational to do so, B subjects often choose to reward A. [Note: “rational” here refers specifically to rational choice theory and not to broader concepts of rationality.]

The Ultimatum Game has been thoroughly studied in a variety of different settings and in tandem with other variables such as culture, status, attractiveness, and gender. The results seem to consistently show that humans tend to act irrationally with some standard of fairness, and are pained when acting or being treated unfairly.

Next we discussed the evolution of human society and culture. As with the discussion of the evolution of morality above, there are two main camps. One camp argues that society evolved due to reciprocal altruism and individual based selection, similarly to the arguments for enlightened self-interest. The other camp argues that society acts as a super-organism and evolved due to group selection. These seem to parallel sociological theories of society (see Meeting 3.3).  In tandem with the evolution of society is the evolution of culture. Again, there are two camps with regards to the interplay between cultural evolution and biological evolution. One camp argues that cultures change too quickly to meaningfully effect biological evolution, and the other camp argues that culture and biological evolution feedback on each other. This lead to a discussion of memes which can be thought of as “cultural genes” that pass information from one generation to the next through books, songs, ideas, etc. Cultural evolution through memes is somewhat controversial because the units of inheritance and a mutational process are difficult to pin down but provides a useful simplification. The group did not reach a formal consensus with regard to the evolution of culture and its interplay with biology, but there was no strong opposition to the idea that genetic and cultural evolution interact.

Lastly, we discussed how behavioral heuristics may be involved in the evolution of human morality and altruism. Heuristics can be thought of as behavioral shortcuts or gut reactions to a stimulus. They apply generally to a wide variety of situations and result in behaviors with little or no “rational thought.” The latter point struck up a discussion in the group of whether rational thought and emotions can be separated, especially when discussing heuristics. Most felt that rational thought and emotions cannot be fully separated, however, again an overall consensus was not reached. The interest in heuristics with respect to the evolution of altruism is whether or not the heuristics humans have evolved are currently adaptive. As with the enlightened self-interest argument, if humans evolved behavioral heuristics during their hunter-gatherer period of evolution where most of the individuals one would encounter were close kin, then heuristics to act altruistically to all would be favored. However, in the modern age where individuals interact with a large number of non-kin, then such heuristics are no longer favored. Group selection could also help explain the evolution of heuristics if acting altruistically toward those in your “in-group” leads to greater group fitness. The discussion of heuristics also sparked a discussion of their cooption toward other animals, namely pets, especially dogs.

To summarize, we discussed the evolution of human altruism and morality and the two overarching schools of thought that attempt to explain the phenomenon. One school favors individual based selection, reciprocal altruism, kin selection and enlightened self-interest. The other favors group selection, and the interaction of genes and culture. Both schools of thought can explain the evolution of heuristics but to different ends. We did not reach any answers or hard conclusions in our discussion, but we certainly left with a lot to ponder over.

            -Zach Grochau-Wright

This week’s reading was an excerpt from Major Transitions in Evolution by Maynard Smith and Szathmary. The particular “major transitions” emphasized in the reading and relevant to discussions of altruism deal with situations where the complexity of a group of organisms increases due to high levels of cooperation and specialization among their constituent members. For example, the evolution of multi-cellularity could be viewed as one such event. In particular, the examples highlighted in the reading included the evolution of eusociality in social insects, as well as the evolution of complex human societies.

We began by discussing social insects. A typical explanation for the evolution of eusociality in insects is some variant of kin selection. Most of the individuals in a colony are highly related (sisters), and hence have an average relatedness to other colony members that is the same as their relatedness to their own offspring (r =1/2 in both cases). This high level of relatedness between colony members is consistent with kin selection-based explanations for the high levels of cooperation and altruistic behavior in these insect species. Haplodiploidy has also been invoked as a potential explanation for the evolution of eusociality in some social insects, such as bees and ants. Haplodiploidy appears to be somewhat correlated with eusociality across several species, in particular hymenopterans (ants, bees, sawflies, and wasps). In hymenopterans, the males are haploid, while the females are diploid. This means that the average relatedness between sisters is 0.75, making it appear to be even more beneficial for a worker to invest resources in her siblings than in her offspring. However, one can refute this argument simply by considering that the average relatedness of workers to the male offspring of the queen is only 0.25, meaning that (assuming a 1:1 sex ratio) the average relatedness to all siblings is still 0.5. Furthermore, many bee species are solitary rather than eusocial, despite being haplodiploid. Nonetheless, it is possible that sex ratios are important for the evolution of eusociality, and thus haplodiploidy may play a role, albeit a much less clear-cut one than originally proposed.

We next discussed the concept of “division of labor”. Broadly speaking, division of labor refers to situations in which the individual units of a system (such as cells in a multicellular organism, individual insects in a colony, or humans in a complex society) take on different functional roles with respect to their behavior and their individual contributions to the activity of the system as a whole. For example, individual cells in a multicellular organism differentiate into different cell types, and termites in a colony take on distinct roles (worker, soldier, etc.). Division of labor typically involves a dramatic increase in the overall complexity of a system, and often allows for a new type of resource to be used, or a new ecological niche to be filled. In this case, the concept of absolute fitness vs. relative fitness becomes important. Absolute fitness (unlike relative fitness) is not defined relative to other individuals in a population, and could increase when a new ecological niche or a new set of resources suddenly becomes available, allowing for (at least temporary) increases in overall reproduction. One could even make the argument that such increases in absolute fitness may be a fundamental driver of increased complexity, although alternative explanations have also been proposed.

Near the end of the meeting we returned to a list of the various definitions or “cases” of altruism discussed at the previous meeting (see the table in blog entry from Feb 13 for definitions, in particular cases 1-4). These cases are distinct from one another primarily because they involve different types of costs (perceived, intended or actual) on the part of the individual performing the altruistic act. One can also approach different notions of altruism with respect to different ways in which the benefits of an altruistic act can be distributed. This is particularly relevant in discussing the evolution of social cooperation. To this end, two additional concepts were introduced:

1) “Loyalty”, which refers to altruistic behavior that benefits members of the in-group more than members of the out-group. One can construct how this might have evolved biologically.

2) What we decided (after some debate) to call “Full Altruism”. “Full Altruism” refers to the case where altruistic behavior benefits the out-group more than the in-group. Unlike loyalty, this type of behavior is much more difficult to explain biologically. Furthermore, the distinction between loyalty and full altruism is especially important for discussions surrounding the ethical and theological dimensions of altruism.

-David Lyttle

We began with a quick review of the history of the concepts of altruism and group selection. We first see these concepts pop up in Charles Darwin’s early works, but Darwin did not formalize these concepts in terms of the mechanisms or mathematics reinforcing them. Wynne-Edwards (1962) introduced the idea of inter-deme selection and the notion of “social conventions” of self-restriction, which act to restrain actions/behaviors at the individual level for the benefit of the group (e.g., Individual A forgoes reproducing so that the group size is restricted, so that the available food resources are not overexploited). It was later shown that Wynne-Edwards strongly overestimated the strength of group selection. Hamilton (1963) first formalized the idea of kin selection, suggesting that genetic reproduction matters, and the level of relatedness (or genetic similarity) impacts the indirect benefits of altruistic acts. In short, the more related individuals are, the more likely they are to be altruistic towards one another. Trivers (1971) was the first big proponent of reciprocal altruism, which involves a pairwise interaction with future benefits in mind. In reciprocal altruism, individuals actually benefit (individual selection) through future pay-back that ultimately benefits the altruistic individual. Wynne-Edwards and Hamilton both came at the idea of altruism from an indirect benefits (group/kin selection) point of view (i.e., altruistic acts lead to increases in the frequency of altruistic genes in the population), whereas Trivers’ reciprocal altruism implies that altruism results from individual selection because of individual pay-offs for the giver of altruistic acts.

This discussion of the history of these concepts led to an offshoot conversation on the differences between group- and individual-level selective pressures. This could be an issue of perspective—the larger your viewpoint (i.e., looking from meta-population level versus sub-population level), the lower the extinction rates and reproductive rates of systems in question. Because of this, lower levels of selection (i.e., at the individual) usually override selection at higher levels (i.e., at the group), when we consider multi-level selection. The group felt comfortable with multi-level selection, but note that some biologists do not believe that group selection is ever relevant in real-world cases. Here we brought up the example of virus evolution, wherein viruses evolve to reduce virulence as a consequence of inter-deme (or group) selection. Why is this a good example of group selection? Viruses must keep their hosts alive long enough to be transmitted into new hosts, otherwise the entire virus population kills itself out (i.e., extinction) by killing off hosts too quickly and therefore cutting off the possibility of transmission of virus particles to new hosts. Therefore, decreasing individual virulence increases the survival of the group of viruses as a whole.

Ok, so if biologists are so unsure about group selection, then why is altruism/group selection such a popular topic? Popular opinion is that group selection is inherent to natural systems. There is a “perfect storm” of public support and common sense knowledge that keeps the idea of group selection rooted in the literature, even though there is a “pro-math anti common-sense” backlash against group selection in the scientific community. So, biologists are concerned about the proliferation of pseudoscientific claims on group selection. Wynne-Edwards made this debate (between public opinion and scientists) worse because his models and ideas were so incredibly intractable and overstretched that they added to the idea that group selection theories belong in the realm of pseudoscience.

From this point, we revisited the concept of the Prisoner’s Dilemma, represented by the payoff matrix below:

       Individual B        Cooperate                            Defect

Individual A

Cooperate                    A = -1, B = -1                     A = -20, B = 0

Defect                         A = 0, B = -20                     A = -10, B = -10

As shown in the payoff matrix, cooperation can benefit everyone in the long run, but in the short run, individuals gain by defecting (or ‘cheating’). No matter what the other individual decides, it’s always best for the individual to defect in the short run, but if EVERYONE always defects then in the long run, average payoff is less than if everyone cooperates. Importantly, single-shot events versus repeated games lead to differences in optimal strategy. Subtleties in strategy changes are linked to differences in the rules of the game (e.g., repeat partners, repeat games, and the idea of tit-for-tat strategies). In fact, despite the presence of tit-for-tat strategists, cooperators may be maintained in a population because reciprocal altruism reduces costs of cooperating over time when cheating is avoided. Reliability of getting a repeat game or interacting with repeat partners also increases the likelihood of cooperation because of pay-off discrepancies. This process may interact with kin selection. If we think of the players as spatially static within a grid, repeat interactions occur between neighboring dots; in nature, kin remain spatially close, and those are at an increased probability of encountering repeat interactions.

At this point, we entered into an aside discussion of the “Tragedy of the Commons.” The phrase refers to the commonly shared resource of grazing fields (e.g., the Boston Commons), that are at risk of overexploitation by individual shepherds if any one individual allows their personal interest to outweigh the interest of the group (i.e., maintaining the resource by restricting herd size per individual).

The rest of the class was spent discussing six different definitions (“cases”) of altruism, summarized in the chart below (with special regard to differences in payoff (P) and cost (C) to the actor). Note that in all cases, the recipient gains a benefit greater than 0.


Defining by Payoff vs. Cost



Case 1 Operational Altruism P < C An observer sees the short-term cost to the altruist exceeding the short-term payoff to the altruist.
Case 2 True Altruism Pi < Ci[The subscript i indicates long-term inclusive fitness.] This may occur, but must be selected against through natural selection; the big question here is, DID you actually get a payoff for altruism or not, even if the payoff was unintentional. Note that in kin selection Case 1 is true but Case 2 is not. [P < C AND  Pi>Ci].
Case 3 Ethical Altruism Actor intends Pi < Ci In evolutionarily adaptive explanations of human altruism, Case 3 is often true, Case 1 is always true, and Case 2 is never true.
Case 4 Theological Altruism Combination of Case 2 and 3 Personal sacrifice for the sake of another is both intended and achieved.
Case 5 Signaled Altruism Giving signal of P < C, whether or not Pi < Ci is true or even P < C “Altruism” has been invoked in sexual selection and social selection as a costly signal.  That signal may be faked.
Case 6 Adapted Altruism P < C but, on average, for past interactions P> Ci[For any particular instance, past or present P> Cimay not be true.] Group, inter-deme, and kin selection as well as reciprocal altruism explain the rise of operational altruism in this way.  Other fully biological explanations of altruism exist, notably where it arises as a side-effect of an adaptation, or where signaling has failed (or been co-opted).

“Biological Altruism” can refer to any biological explanation of altruism.

Britt Singletary, Anna Dornhaus, Lucas Mix

This week involved many introductions- after introducing ourselves and our backgrounds, we jumped into basic evolutionary theory. We discussed how replicating populations evolve and the criteria for biological evolution. There are three main criteria: some trait is variable in a population, this trait value affects an individual’s reproduction, and this trait is heritable to a parent’s offspring. From a classical perspective of evolution we need only track organisms. We can also look at evolution from a Hamiltonian perspective, which focuses more on selection for genes than selection for organisms. It’s important to remember that these are alternative, non-conflicting, frameworks for viewing biological evolution.

As well, we introduced the concept of relatedness between individuals as the probability of two individuals sharing the same genes. Thus your relatedness to your mother is r=0.5, your relatedness to your sibling is r=0.5, and your relatedness to your cousin is r=0.125. This is the source of JBS Haldane’s quip “I would [give my life] to save two brothers or eight cousins.”

We introduced several terms:

Kin selection: when an organism acts with personal cost to the evolutionary benefit of closely related members. Example: JBS Haldane jumping into a river to save two of his brothers.

Group selection: when individuals form groups and selection is operating on the group. This occurs in special cases where some groups may reproduce. Example: loss of virulence in Myxoma virus infecting Australian rabbits.

Multi-Level Selection: the idea that genes, organisms, and groups may all be the locus of selection.

Reciprocal altruism: when an individual acts with immediate personal cost with expectation (implicitly or explicitly) of returned benefit later. In the long run, individuals thus exchange benefits  Example: blood feeding among vampire bats.

Prisoner’s Dilemma: game theory problem where two individuals compete. Due to the specific pay-offs of cooperating and cheating, the rational choice of each player is to cheat, regardless of whether the other person cooperates or cheats. However, mutual cheating is a worse outcome for each player than mutual cooperation.

Tragedy of the Commons: the multiplayer version of the Prisoner’s Dilemma where each player is tempted to overuse a common good; however, this may lead to exploitation of the common good. Example: fisheries population.

Operational altruism: behavior that appears to include immediate costs to the actor and benefits to a recipient, setting aside questions of whether it was intentional or has long term benefits.


Lastly, we discussed the difference between biological altruism and ethical altruism. If we define ethical altruism as “intending to act without benefit to self”, then altruism seen in biological circumstances may or may not fulfill this definition. Evolutionary explanations always refer to what we’ve termed ‘operational altruism’. So organisms sometimes display behaviors that appear ‘altruistic’ in the ethical sense but actually aren’t. Thus operational altruism may be explained as ethical altruism AND/OR explained by evolutionary processes such as the ones above. Interesting areas we will explore in ethical altruism include self-sacrificial will and the ability to promote normative ethical principles.

As we wrapped up our class, we mentioned several questions that will come into play in the future.


  1. How do genes produce (or influence) behavior?
  2. How can we identify which model of altruism fits an observed phenomenon (particularly interesting in group selection versus kin selection discussions)?
  3. What human behaviors can we explain using a discussion of altruism?


Semester 6 Summary: Will or No

Sarah Williams provided this great perspective on the scope of semester 6, in which we discussed Cognitive Neuroscience and Free Will.  She highlights elements of each discussion.

6.1: Sam Harris’ view: There is no agency. This is the case for two reasons:

1)    Agency can only be conscious and never unconscious. There is no conscious agency because all conscious choice is determined completely by unconscious causes. Some empirical support of this claim is found in the Libet (1983), Wegner (2002) and Ebert & Wegner (2010) experiments.

2)    Contemporary physical theory does not support the existence of agents.

Some problems with Harris’ view could include the fact that we seem to have conscious control over conditioning our impulse control and over how our brains respond to stimuli. If there was support for unconscious agency it would also be problematic for the argument. The causal chain of our behavior consists of several stages. Harris’ claim requires that the first cause be at the level of our neurobiology. This seems arbitrary, and Harris does not offer support for why this must be the case.

6.2 Daniel Kahneman’s view:

Human cognition operates using two systems, System 1 (for immediate, automatic responses) and System 2 (for less immediate, more complex calculations). Both systems use heuristics, but they are automatic for System 1 and conscious for System 2. A brief summary of the two systems:

System 1: automatic, short time scale, no voluntary control or conscious effort needed, metabolically less costly, trainable by conditioning, handles familiar tasks.

System 2: conscious, deliberate and requiring mental effort, metabolically more costly, handles complex and novel tasks, can take over some system 1 tasks.

From an evolutionary standpoint, having a fast, metabolically cheap system that can be trained to handle repetitive tasks and situations, and a slower, more deliberative system that can train the fast system seems like a useful adaptation given our limited ability to process stimuli (invisible gorilla experiment) and our limited metabolic resources (ego depletion).

Kahneman’s paper added a new dimension to the discussion on free will. System 1 handles seemingly unconscious activities and System 1 can be trained by our conscious System 2, does this mean that there ultimately is a form of unconscious agency?

6.3 Shaun Nichols’ view:

Most people think that they have agency, but seem to mistake a difference in the antecedent conditions with actual agency. These intuitions track indeterminist agency/free will. We probably have these intuitions because they most closely describe the way we experience our actions. When we are at a decision point, we experience that all of the antecedent conditions are fixed and yet we still believe that we have the option to choose differently.

However, these intuitions do not adequately justify indeterminism for a number of reasons:

  • Our experiences could be informed by determined causes
  • The indeterministic perspective could be learned/conditioned
  • Raw experience as a counterfactual doesn’t really make sense. Something like a toothache is primary, whereas counterfactuals are a second order analysis of primary experiences.
  • Spinoza: We believe in indeterminist free will because we are ignorant of the actual causes of our actions
  • We don’t have introspective access to all the factors that influence our choices (in response to Glimcher’s argument)

6.4 Roy Baumeister’s view:

Choice is not an epiphenomenon, lacking causal power over our actions. Conscious thought does influence actions (although, so does unconscious thought). Some examples: mental rehearsing and simulation of actions, planning, reflection, counterfactual reasoning, and overriding automatic behaviors. Conscious thought and unconscious thought have a two-way influence over each other via priming (unconscious influences conscious) and conditioning/learning/synaptic plasticity (conscious influences unconscious).

For dualists, this influence could also be non-physical.

Baumeister is attempting to counter the view that conscious thought is a “steam whistle,” having no influence on our behavior and existing as an epiphenomenon of our unconscious processes.

6.5 History of Will:

The views of the Greeks:

There were two major camps that divided over whether choice was found in the head/brain area/organ of our bodies or the heart area/organ. Plato was in the “head” camp. He located virtue/masculinity/energy in the chest. This contrasts with Aristotle, who located all three aspects (Rational/Motive/Nutritive) in the heart. For Aristotle, the brain was merely a cooling device for the blood.

Some historical views:

Thomas Aquinas separated the processes into worldly/imperfect and extra-wordly/perfect. Our senses perceived the data from the world and we processed this information with our common sense (physical), while our intellect perceived the perfect realm of ideas (spiritual – akin to Plato’s Forms). Only humans have intellect, while animals and humans have common sense. Descartes combined common sense, intellect and will into the concept of the mind and located it outside the physical realm. Contemporary neuroscientists suggest that there is no one seat of consciousness, will or identity.

6.6 How to define agency:

  • If agency is defined as intent, this implies a relationship with another entity, living or otherwise. Atoms could not have agency, however, because they must follow a set of rules.
  • If agency is the ability to make rules, then it can be easily related to morality.
  • If we have an attitude of approval toward some options or the consequences of those options more than others, morality could be a way to express those attitudes. (I phrased this differently than the summary on the blog because I thought it was heavily biased toward a consequentialist interpretation of morality. I use the word attitude technically here.)
  • Whatever the choice available, value and reason ought to be used to evaluate which choice should be picked. If we lose the concept of agency, we seem to lose the concept of rationality. The sense of accountability and responsibility are both grounded in our sense of agency.

What if there is no such thing as agency?

Perhaps Spinoza is right: we invented agency as a way to make sense of cognitive dissonance or to explain our experience of the world. To relieve ourselves of this misconception would not necessarily have any impact on the institutions of punishment or morality.

Perhaps the question of agency and free will hinges on whether it is possible to have a bifurcating universe, as agency requires this. Sub-atomic physical stochasticity complicates the question of a bifurcating universe, as ultimate causes are obscured and the limits of observation may cover true determinism, contingency, or will.

With the advances in neuroscience, social behavior theory and complex dynamical systems theory, how can moral agency, one of the classic examples of human “uniqueness”, be reconstructed?

6.7 Emergence:

Moral agency may be an emergent property of consciousness.

Weak emergence: Complex systems produce patterns that, by convention, are modeled or described in terms of higher-order properties: i.e. human thought emerges from interactions between large numbers of neurons, social insect colonies emerge from the interactions of many individual insects (I think this is an entailment relation from the lower to the higher processes). Weak emergence is widely accepted and uncontroversial.

Strong emergence: the higher-order phenomena that emerge from lower level processes are not causally determined by them (this is a supervenient relation, see: http://plato.stanford.edu/entries/supervenience/ – 3.2). This has the characteristics of dualism. This is the more controversial of the two views.

Consensus on the topic of agency was not an emergent property of this forum!