By: John R. Evers
I. Introduction: Genes and Altruism
Charles Darwin described the sterility of certain castes of social insects, and more generally, the reproductive self-sacrifice such organisms represented, as "one special difficulty, which at first appeared to me insuperable, and actually fatal to my whole theory."[1] In the 1960's, W.D. Hamilton "inaugurated" the theory of "kin selection," which offered a brilliantly simple explanation for such altruistic behavior.[2] As Holldobler and Wilson explain, "Hamilton recognized the importance of a measure he called inclusive fitness, which incorporates both the individual's personal reproduction (classical fitness) and its influence on the reproduction of collateral relatives."[3]
The essentials of kin selection and inclusive fitness are summarized according to a simple equation, called "Hamilton's Rule," which is expressed: C/B < b. "This says that the cost C (which is the loss in expected personal reproductive success through the self-sacrificing behavior) divided by the benefit B (the increase in the relatives' expected reproductive success) must be less than b, the probability that the relatives have the same allele,"[4] if the altruist gene is to survive natural selection.
Inclusive fitness begins by focusing solely at the level of the gene, but then widens that focus to encompass the entire group or population comprising any given gene's extant copy-set. For example, assume organism X is a carrier of gene-A and that gene-A causes X to behave in a certain way which kills X prior to the production of any offspring. If X's suicidal behavior directly enhances the survival and reproductive potential of X's siblings, gene-A still has a chance at survival and even proliferation - not in X or X's non-existent offspring, but in X's siblings and their offspring since at least some of X's siblings will carry copies of gene-A. One copy of gene-A is just as good as the next; any single gene-copy is just as transitory as the organism which carries it.[5] Indeed, inclusive fitness demonstrates that the true fundamental unit of natural selection is a gene's entire copy-set.
For this reason, in the expression C/B < b, everything hinges on b - the probability that the altruist's siblings carry copies of the same altruist gene. As Dawkins observed, "[k]in selection accounts for within-family altruism; the closer the relationship, the stronger the selection."[6] Thus, the "family" is merely a short-hand approximation of a representative portion of any given gene's copy-set (according to the degree of relation within the family), and changing degrees of relatedness will directly effect levels of intra-family altruism.[7]
The obvious limitation of Hamilton's Rule is that it only justifies altruism expressed within the family. Alternative theories, such as reciprocal altruism, can account for the natural selection of generally cooperative behavior regardless of familial relationships, but theories such as reciprocal altruism do not necessarily account for altruism.[8] As Wright points out, "[reciprocal altruism] doesn't involve sacrifice for anyone who doesn't ultimately reciprocate."[9] Hence, reciprocal altruism does not account for "sacrifice" at all. For the purposes of this analysis, an organism that is to be considered an "altruist" must suffer a net cost (in terms of reproductive potential) as a result of its behavior, as it was primarily this feature that established the monumental problem which challenged Darwin in 1859 and which was solved in part by Hamilton's Rule.
The intra-family limitation of Hamilton's Rule is a result of a certain feature of genetic reproduction; namely, that genes can only produce copies by making new carrier organisms in which to house these copies. In other words, gene copies are only distributed vertically (down family trees) within a population. Because genes distribute their copies in this fashion, the only easily identifiable groups of organisms that will have some a priori reason for possessing high b values in Hamilton's Rule is the genetic family. Thus, while Hamilton's Rule may have solved the paradox of completely self-sacrificial behavior within the confines of the genetic family, it simultaneously precludes the possibility of altruism directed beyond the genetic family since it is unlikely that a random, non-family member will share a copy of the relevant altruistic gene. When C/B is less than b, self-sacrificing behavior can be seen as successful altruism; but, when C/B is greater than b, the same behavior begins to look more like genetic suicide. In fact, altruism of any degree should face the threat of competitive elimination where the b-value is zero.
Moreover, any benefit enjoyed by an organism not carrying the altruist gene (a "non-carrier") will necessarily dilute the net benefit that would otherwise accrue to the altruist gene's copy-set. Therefore, if an altruist gene is to succeed, some mechanism must evolve which can eliminate (or, at least, offset) this potential dilution. By functioning to decrease any potential benefit to competitors and increase potential benefit to the altruist gene's copy-set, this mechanism will manifest itself generally as an increase in competition between carriers of the altruist gene and their non-carrier competitors. Thus, the inverse operation of Hamilton's Rule dictates levels of inter-family competition generally proportional to any degree of intra-family altruism.
However, if some non-genetic unit of natural selection can allow for a sufficiently high b-value among non-siblings (i.e., between any randomly selected members of a population), then the threat posed by the inverse operation of Hamilton's Rule is removed. Richard Dawkins introduced the generally accepted name for this alternative unit of natural selection: it is the "meme."[10]
II. Memes and Altruism
Any meme can be defined generally as a rule of behavior, encoded by functional neuronal groups or pathways. Behavior is action, whether mental or physical. Ideas such as tying shoe-laces or opening a door represent rules of physical action, i.e., rules of patterned neural-muscular interaction. Concepts such as apple, seven, or causality, represent rules of mental action, or rules of cognition, i.e., rules of patterned neural-neural interaction. Hence, physical movement is governed by memes which represent rules of physical action and thought is governed by memes which represent rules of mental action.[11]
If memes are units of natural selection (allowing for a memetic application of Hamilton's Rule); and, if memes copy horizontally (allowing the "memetic family" to extend beyond the scope of the genetic family); and, if memes can be directly responsible for altruistic behavior, then memetically driven and inclusively fit altruism can extend to the whole of any given (freely communicating) human population according to the mathematical purity of Hamilton's Rule.
A. Memes as units of selection
Most, if note all, models of selection share three basic elements: (1) variability of base units; (2) competition between base units for reproductive resources, or selective pressure; and, (3) selective reproduction (or, selective longevity).[12] Memetic variation is demonstrated by the approximately one trillion (1,000,000,000,000) neurons which make up the average human brain, with the cerebral cortex accounting for at least 50 billion of these nerve cells.[13] Moreover, because anyone who wants to share any idea with another person must create a physical substrate for the idea (e.g., language, whether spoken or written), the full scope of memetic variability is most accurately described by combining the subjective knowledge of each living human carrier with the full body of extant objective knowledge (e.g., knowledge encoded in books, or computers).
Considering a meme as a discrete neural group or pathway, it follows that memetic competition is fueled by the need for (finite) neurochemical resources and (limited) neural space.[14] That neural patterns or neural groups compete for space and neurochemical resources is not a novel proposition.[15] Thus, memetic competition for the limited space and biochemical resources available in the brain can be restated simply as competition between neurons or functional groups of neurons for stimulation.
Rules of behavior which are followed and reinforced to increase the probability of future stimulation are remembered. Memes which fail to acquire the necessary resources for reproduction, whether manifested in physiological or non-organic material substrates, will face competitive elimination, i.e., they will be forgotten. Every human activity, from basic cognition to daily "decision-making," can be seen as a process of natural selection during which functional neuronal groups compete to occupy a behavioral (whether mental or physical) niche within a carrier organism's nervous system. Hence, certain memes are selected over others based on the neurochemical characteristics of the underlying neuronal group(s) or pathway(s), as well as their resulting classical and inclusive fitness.
B. Horizontal Memetic Reproduction and Altruistic Memes
The second and third demonstrations, that memes are capable of horizontal reproduction and that memes are capable of encoding altruistic behavior (assuming such behavior exists at all), are easily made as they are both self-evident propositions.
Genetic reproduction occurs through an elaborate process of cellular fusion and the consequential growth and maturation of newly formed carrier organisms. Memetic reproduction occurs through an equally elaborate processes of imitation and/or linguistic communication, whereby memes are copied from one nervous system into another. That memes are capable of horizontal reproduction (i.e., that memes are not limited to copy distribution within genetic families) is a self-evident proposition, provided the recipient of the proposition is not a genetic sibling of the one advancing the proposition. Indeed, any attempt to dispute the proposition that human beings generally are capable of sharing ideas is to advance or attempt to share the idea that ideas cannot be shared. Therefore, it is literally beyond argument that memes are capable of horizontal reproduction.
Finally, while genes encode the assembly of polypeptides and thereby transcribe physiological structure, memes represent patterns of neural stimulation and thereby transcribe behavior. Therefore, if anything is to be directly responsible for altruistic behavior it will be a meme, whether the meme is genetically encoded (i.e., innately acquired), or learned (i.e., environmentally acquired).[16]
III. Memetic Application of Hamilton's Rule
As currently applied, Hamilton's Rule is based solely on the static nature of genetic identity: because an organism's genetic makeup is fixed for the duration of the organism's lifespan, any two organisms will either share a copy of a gene or they will not, and this objective fact is measured according to probability and familial relation. However, since memes are capable of horizontal reproduction (whether through imitation or linguistic communication), it is possible that any meme, including an altruist meme, could express itself in favor of (and, therefore, presumably in the presence of) a non-carrier competitor and thereby copy itself into the memetic (i.e., neuronal) structure of the competitor. In short, a competitor directly experiencing the benefits of another's self-sacrifice might subsequently imitate such altruistic behavior for no other reason than having experienced such behavior first-hand. Consequently, one should expect various factors (whether genetically encoded, memetically encoded, or both) to evolve throughout a population which would enhance or detract from the probability of such imitation (e.g., empathy, admiration, so-called "open-" or "close-mindedness," etc.).[17] Any given meme or set of memes could likewise evolve various mechanisms to increase the probability of such imitation (e.g., cognitive or psychological appeal, etc.).[18] Hence, it is conceivable that some factor or set of factors could be delineated that would determine the relative rate of conversion (from non-carrier-competitor to carrier-clone) for any given meme within a certain population.
This rate of conversion shall be expressed as a new variable, to be added to the right side of Hamilton's Rule since it will operate to increase the likelihood that the beneficiary organism(s) will carry a copy of the same altruistic meme (following the altruistic encounter). Because the rate of conversion will have no application where a beneficiary already carries a copy of the altruist meme, it will only modify the probability that a beneficiary does not carry a copy of the altruist meme, which is described by (1-b). Therefore, the memetically adapted Rule is: C/B = b + c(1-b), where the rate of conversion [c] measures the likelihood that expression of a meme will "infect" a non-carrier and thereby convert the non-carrier into a carrier.
Operation of this adapted version of Hamilton's Rule can be stated as follows. Assume that there exists a 1/4 (or 25%) degree of memetic relation within an intra-communicating population. Hence, each member of this population shares roughly 1/4 (or 25%) of the same memes. Assume also that a member of this population carries an altruist meme that has a conversion rate of 3/4 (or 75%). Hence, for every four non-carriers, three will be converted into carriers upon contact with the meme. According to these figures, there is a 13/16 (or, 81.25%) chance that expression of this meme in favor of any randomly selected member of the population will operate to confer a direct benefit on a representative member of the altruist meme's copy-set. Whether a net benefit is likely to be conferred by expression of that meme will depend on comparing this figure with the Cost-Benefit ratio defined by the left side of Hamilton's Rule.
IV. Conclusion
According to the memetic application of Hamilton's Rule, the key
factor to success for altruistic behavior is not a high probability of
clone status (with regard to the altruistic gene) based on genetic familial
relation, but a high probability of clone status (with regard to the altruistic
meme), based on a population's horizontal reproductive fertility. Indeed,
a highly infectious, altruistic meme (e.g., 80% conversion rate) existing
in a small fraction (e.g., 10%) of the population would still enjoy a very
high probability (72%) that expression of any copy, in favor of any random
member of the population, would serve to benefit that meme's (growing)
copy-set (all other things being equal). Assuming acceptable criteria and
empirical data can be established to give real meaning to the "rate of
conversion" for any given meme, the memetic application of Hamilton's Rule
offers a comprehensive justification for general (intra-societal, or intra-cultural)
altruism. Meanwhile, it can be said with newfound certainty that purely
altruistic behavior is possible within any memetically fertile population.
[1]Holldobler and Wilson, The Ants, (Harvard University Press, 1990), at p.181.
[2]Id.
[3]Id.
[4]Id.
[5]A sequence of nucleotides which dictates the construction of a specific polypeptide can be classified as a "gene," and can be analyzed as being fit or unfit according to natural selection; but, it cannot be called a "survivor." Likewise, a discrete quantum of functionally synchronized neurons can be classified as a "meme," and can be analyzed as being fit or unfit according to natural selection; but, it cannot be called a "survivor." Any particular sequence of nucleotides or quantum of neurons will degrade prior to or contemporaneous with the death of the carrier organism. Indeed, nucleotides and neurons are as much a part of the organism as is any protein, enzyme, cell, organ, or physiological system. The only thing that is carried by an organism (in the sense that it can outlast the organism) is the underlying pattern of nucleotides or neurons, which exists purely as a speculative construct of subjective consciousness. The concept of the potentially immortal gene/meme can be made to represent a concrete reality only by redefining the functional "gene" or "meme" as the total extant copy-set of any given particular genetic/memetic manifestation, i.e., as a population of gene/meme copies. Any individual member of such a population may be transitory, but the population itself can survive indefinitely.
[6]Richard Dawkins, The Selfish Gene (Oxford University Press, 1989), at p. 94.
[7]See e.g., Robert Wright, The Moral Animal (Vintage Books, 1994), at 164.
[8] See Dawkins, The Selfish Gene, supra note 6, pp. 202-233 for explanations of various strategies for cooperation and mutual benefit. See also, Wright, The Moral Animal, supra note 7, at pp. 189-209. According to Wright, reciprocal altruism is the only available explanation for inter-family altruism and, therefore, "wins by default." Id. at 202.
[9] The Moral Animal, supra note 7, at p.207.
[10]The Selfish Gene, supra note 6, at p. 192.
[11]A possible third category of action is linguistic action, which represents a means of converting physical action into mental action, i.e., language is movement that encodes thought.
[12]See e.g., Edelman, Neural Darwinism (Basic Books, 1987), at p. 9.
[13] Kandel & Schwartz, eds., Principles of Neural Science (N.Y.: Elsevier Science Publishing Co., 2nd Ed. 1985), at 223.
[14]It also follows that memes compete for access to the limited and finite materials required for manifestation in non-organic memetic carriers, e.g., book space, computer storage space, etc.
[15]For example, Edelman describes the "Mnemon hypothesis," proposed by J.Z. Young in 1965, which describes a means for selective competition amongst neuronal groups competing for stimulation. (Neural Darwinism, supra note ___, at 14-15). Edelman's own theory of neuronal group selection is based on the concept of neuronal competition for stimulation. (Id. at pp. 45-46).
[16]For the purposes of this analysis, innate behavior describes behavior which is the immediate result of memetic expression, but which is ultimately the result of genetic expression, i.e., the responsible memes are formed as a result of genetic expression. Learned behavior is the product of environmentally acquired memes which are, in turn, the product of epigenetic, somatic selection. An innately acquired meme that is incapable of horizontal reproduction is the functional equivalent of a gene.
[17]See generally Aaron Lynch, Thought Contagion (Basic Books, 1996), at pp.2-16.
[18]Id.