The ultimate result of the rule of natural selection is the competitive, vicious side of nature.1
By Leonard Brand and Arthur Chadwick
As it attempts to explain animal behavior, evolution has a problem with altruistic behavior (behavior that benefits another individual while possibly endangering oneself). Natural selection should not allow altruism to evolve.
The theory of sociobiology was the proposed solution to this problem. According to sociobiology, if individuals seem to be helping other individuals at their own expense, they are doing this only when those being helped are close relatives (kin selection) who can pass on genes shared with the one who is helping. Since the helper’s genes are passed on because a relative was saved, the result is actually supposed to be in favor of the helper, and thus is not really altruistic.
Evidence for this can be found in the animal world. The theory has also been applied to humans and has been used to justify immoral behavior. Even rape is seen as just another strategy to pass on one’s genes. These conclusions are dependent on the assumption that humans and other animals evolved from common ancestors, but sociobiology does not provide evidence for that evolution. Perhaps mutations after humans fell into sin have favored the more selfish side of our nature, but Christianity offers a solution, as we seek divine support to become more like Jesus Christ.
Animal Behavior and Evolution
The theory of sociobiology, the application of evolutionary theory to the study of behavior, developed as scientists searched for a more adequate evolutionary explanation for all forms of animal and human social behavior. There is a process whereby mutation, recombination, and natural selection can introduce a trait into a population. For example, a variation in color could make an animal better camouflaged. If the individuals with the new color survive and reproduce more successfully, the new color variant would become more common in the population. The impact on the next generation is determined entirely by how many offspring are produced that have the new color gene. The ability of organisms to reproduce successfully is described by the term fitness. The individuals that produce the most reproductively successful offspring have the highest evolutionary fitness.
One can visualize how this functions in the case of morphological features such as selection between color variations (improving camouflage), between individuals that differ in size or strength (ability to secure food and defend against enemies), or in speed (ability to escape). Could the same process be involved in explaining evolutionary changes in behavior? Could it explain why some species have monogamous mating systems and some are promiscuous, or why some species rely more on vocal communication and others focus on chemical communication?
Ewer summarized this challenge with his statement that “unless the mechanisms which produce the behavior are explicable in terms of natural selection working in the orthodox manner, we will be forced to postulate special creation or some unknown mystical-magical process.”2 In many cases, microevolutionary explanations for the origins of behaviors could be suggested. A problem remained, however, in attempting to explain altruistic behavior. An altruistic act is any behavior that benefits another individual at the expense of or risk to the one performing the behavior. Darwinian reasoning seems to predict that an individual animal would compete to survive rather than act selflessly toward other individuals, especially if that act may jeopardize its own survival.
A ground squirrel that gives an alarm call when a hawk appears warns others to hide, but it also draws attention to itself and may even increase the chances that it will be the one caught by the hawk. In evolutionary terms, a squirrel that is prone to give alarm calls may be decreasing its own fitness because it is decreasing the probability that it will live to reproduce. A squirrel whose genes predispose it to cheat, by benefiting from the alarm calls of others but not giving calls itself, would appear to be the one with the best chances of reproductive success, and thus have the highest fitness.
Some species of birds, such as the Florida scrub jay or the African bee eaters, have nests that are cared for by the parents with the assistance of one or more other adult “helpers at the nest.” Why would one of these helpers decrease its own fitness to help other birds raise their young rather than raising young that carry its own genes? Can evolutionary theory explain this?
Many who accept some form of creation by God consider the creation of humanity and morality to have been a separate and special act from other acts of creation. Therefore, an interventionist is tempted simply to dismiss any proposed evolutionary mechanisms for explaining altruistic behaviors. Even interventionists, however, must explain why evolutionary processes after the creation event appear to have eliminated many altruistic behaviors. Consequently, the question regarding altruism in animals remains essentially the same for everyone, no matter what philosophy anyone starts from.
Sociobiology: A Proposed Answer to Altruism
In 1975, Harvard entomology professor Edward O. Wilson published Sociobiology: The New Synthesis. In it, he defined a new paradigm: “the systematic study of the biological basis of all social behavior, . . . a branch of evolutionary biology and particularly of modern population biology.”3 This paradigm stimulated considerable controversy, but much of it has been generally accepted.
In Sociobiology, Wilson claims to have solved the problem of altruism. A cornerstone of sociobiology theory is the concept of inclusive fitness, which refers to the rate at which an animal’s own offspring and its close relatives’ offspring are successfully reared and reproduce. While fitness is an animal’s rate of success in passing its genes to its own offspring, inclusive fitness is its rate of success in passing its genes directly to its own offspring and indirectly to the offspring of its close relatives, because its relatives have many of those same genes. Two sisters share, on the average, 50 percent of their genes in common. If one sister helps the other to successfully raise her offspring to reproductive age, she assists in the passing on of many genes that she shares with her nephews and nieces, thus increasing her inclusive fitness.
Sociobiology theory predicts that, because of this sharing of genes between relatives, altruistic behavior should exist only in situations in which the altruistic individual would actually increase its inclusive fitness by that behavior. Biologist J. B. S. Haldane is reputed to have once said that he would lay down his life for two brothers or eight cousins. The reason for this is that, on average, brothers share half of their genes and first cousins share one-eighth of their genes. If Haldane died for one brother (thus eliminating his own chance to reproduce), his brother could only pass on half as many of J. B. S. Haldane’s genes as J. B. S. himself could have done. However, if he died to save two siblings, he would, statistically speaking, come out even.
If this is applied to alarm-calling squirrels, sociobiology theory predicts that squirrels should be most likely to give alarm calls when they are surrounded by many close relatives. Hence, the squirrels that are helped by the calls share many genes with the caller, thus increasing the caller’s inclusive fitness. Research has shown this is true. When young ground squirrels mature, the males disperse to distant places before they settle down and choose a territory. Young females do not disperse. They set up territories near home. Consequently, females have many close relatives living near them, but males do not. Just as the theory predicts, it is the females who give the alarm calls. When a female calls, many of the squirrels who are helped are relatives who share her genes. Even if she is caught by the predator, her relatives who run for cover will pass on her genes that caused her to give the alarm call.4 Natural selection in this situation is called kin selection. Favorable traits are shared by close relatives, and a family that helps its members survive will have more reproductive success than other families. Their behavioral traits are the ones that will become more common.
The processes of mutation and kin selection, and their effects on inclusive fitness, are the elements of the mechanism by which sociobiology proposes to explain the origin of altruism and of all other social behavior. Sociobiology theory says that the entire focus of life is reproductive success. Animals are “sex machines,”5 whose function is to pass on favorable genes that will improve the inclusive fitness of their offspring.
The evolution process has no room for unselfish actions that help a non-kin at the expense of the one performing the action. Thus, one corollary of sociobiology theory is that there is no such thing as truly altruistic behavior. Some apparent exceptions to this are explained as “reciprocal altruism”—you scratch my back, and I’ll scratch yours. For example, an olive baboon male will solicit help from an unrelated male in an aggressive interaction against a third male. It often occurs that on another occasion the roles are reversed, and the original solicitor helps the same partner who is now the solicitor.6
Can sociobiology explain the helpers at the nest? Kin selection would predict that a bird nest has non-parent adult helpers only when the helpers’ inclusive fitness is higher from helping relatives than from trying to raise their own young. Research has confirmed that this prediction is correct,7 and that the helpers are close relatives, usually offspring from a previous season. These helpers cannot secure territories of their own or are too inexperienced to be very successful in raising their own young in their first year. Until they are ready to do so, their inclusive fitness will be higher if they help raise their relatives who share many of their genes.
As animals compete with one another for resources such as food, living space, or mates, various behavioral strategies could be employed. The application of sociobiology theory suggests ways to predict which strategy will be most effective in different situations. For example, two competitors could simply fight, with the winner of the fight taking the resource. They could employ some type of conventional strategy (symbolic battle), like a stereotyped arm-wrestling match, that indicates which animal is stronger or more aggressive without the risk of anyone getting hurt. Game theory and the principles of sociobiology can be used to predict the benefits of each strategy. Natural selection, in general, is expected to favor conventional strategies over all-out “war” in animal conflicts. Many examples of this can be seen in nature.8 Male rattlesnakes don’t bite other males, but wrestle one another, and the winner is the one that can pin the other’s head to the ground with his own body. Lava lizards “battle” by hitting one another with their tails, and marine iguanas butt heads together and push one another backward. Deer and antelopes have potentially lethal antlers or horns, but when the males battle over mates they do not try to impale each other. They butt their heads together and wrestle in ways that usually do not cause serious damage. Animals also commonly communicate the nature of their aggressive state to other individuals of their species, apparently to allow the other individual to respond appropriately, thus reducing the amount of fighting.
Research under the guidance of sociobiology theory has led ethologists (scientists who study natural behavior of wild animals) to recognize the role of some animal behaviors previously thought to be only bizarre abnormalities. For instance, a male African lion sometimes kills all the cubs in his pride. This happens when a battle between males occurs, and the ruler of the pride is deposed. The new dominant male generally kills all of the young, the offspring of his deposed rival. Consequently, he is able to mate and produce his own offspring much more quickly than if the females were occupied with offspring of his former rival.9 Such infanticide is also known to occur in Hanaman langurs, mountain gorillas, chimpanzees, African wild dogs, and rodents.
Implications for Human Behavior
Sociobiology has become the prevailing synthesis in the study of animal behavior and has been very successful. Apparently, sociobiological reasoning frequently provides useful and testable scientific predictions in animal-behavior studies. What are its implications for human behavior?
The basic claim of sociobiology is that human behavioral traits are not a result of special creation. They have developed through evolution from non-human ancestors. Increased inclusive fitness is gained by increased reproduction by oneself or one’s close relatives. Consequently, according to sociobiology, reproductive success is the dominant factor determining human behavioral tendencies. Though we may think that we are rational, moral beings, our behavior is more programmed than we think it is. In other words, “sociobiologists contend, we were designed to be reproduction machines.”10
Christians believe that humankind has been given a set of moral rules for sexual behavior. These rules tell us what is right or beneficial and what is wrong and should be avoided simply because it is damaging to human relationships or is harmful to ourselves or others.
Sociobiology says there are no morally right or wrong behaviors. Our behavior is the result of the selection pressures that have created us. Anderson summarized the concept this way: “The type of man who leaves the most descendants is the one who cuts his reproductive costs on all sides, by keeping a close watch on his mate and making sure he has no rivals; supporting his mate, if it seems that all her children were sired by him; and mating with other females—additional wives, single women, other men’s wives—whenever a safe opportunity arises.”11 Some researchers suggest that evolution has programmed us so that babies do not look too much like their fathers, thus making adultery easier to get by with.
Sociobiology: An Alternative to Religion
In sociobiology theory, right or wrong behavior does not exist in a moral sense, only different behavioral strategies with effects on inclusive fitness. Sociobiology could be said to be the naturalistic answer to Christianity’s value system. “Wilson openly challenges Christian faith by offering a substitute belief system based upon scientific materialism.”12 Wilson believes that humanity has an innate tendency toward religious belief because, in the past, it conferred an adaptive advantage. He also believes that the content of religious belief is false, and that we should replace it with a more correct mythology. “This mythopoeic drive [i.e., the tendency toward religious belief] can be harnessed to learning and the rational search for human progress if we finally concede that scientific materialism is itself a mythology defined in the noble sense.”13 He urges us to “make no mistake about the power of scientific materialism. It presents the human mind with an alternative mythology that until now has always, point for point in zones of conflict, defeated traditional religion.”14
Wilson does not deny that religion and moralism have value. He believes they can encourage reciprocally altruistic behavior by discouraging cheating. But he believes that moral values should be determined by science, which offers the “possibility of explaining traditional religion by the mechanistic models of evolutionary biology. . . . If religion, including the dogmatic secular ideologies, can be systematically analyzed and explained as a product of the brain’s evolution, its power as an external source of morality will be gone forever.”15 Wilson feels our ideas of sexual morality should be more liberal. He bases this conclusion on a survey of the behavior of our presumed nonhuman ancestors and on his convictions that Christianity’s moral laws did not come from God. These opinions apparently are based on his conclusion that with continuing research “we will see with increasing clarity that the biological god does not exist and scientific materialism provides the more nearly correct perception of the human condition.”16
Is Sociobiology Real?
To what extent are the proponents of sociobiology correct? To address this question, several concepts can be isolated and considered.
• The proposed naturalistic origin of the higher groups of organisms, including the origin of humanity and the human brain. Sociobiology theory, as proposed by Wilson, is based on the assumption of the naturalistic evolutionary descent of all organisms from a common ancestor. Sociobiology does not, however, provide evidence for that evolutionary descent. It merely assumes the naturalistic evolutionary origin of animals and develops hypotheses and explanations for behavioral change based on that assumption.
• Kin selection and the evolution of behavior, at the level of species or genera of animals. The alarm-calling female ground squirrels, the bird helpers at the nest, and a host of other examples certainly fit the theory very well. Whether future research will continue to support it remains to be seen. Late in his career, Wilson (controversially) abandoned his support of kin selection, believing rather that group selection (selection operating at the community level rather than on the individual level) is where sociobiology functions.17 But with mutations causing random damage to the genes that influence behavior, it does seem very likely that behaviors not supported by some type of selection process eventually would be weakened or eliminated, perhaps by epigenetic processes.
• Kin selection and its genetic influence on human behavior. Aside from the question of whether humankind is the result of evolution, one can ask whether human behavior is controlled by genes, as claimed by sociobiology, or determined mostly by culture (i.e., learned rather than inherited). This debate has raged ever since (and before) sociobiology was introduced. Wilson actually does recognize that culture is an important component of human behavior, but he maintains that other important themes of primate behavior also are present in humans by inheritance.18 Others disagree. This group includes scientists who believe Wilson’s sociobiology goes too far in presuming biological determinism.
Perhaps the most widely known challenger of biological determinism was Stephen J. Gould, a colleague of Wilson’s at Harvard. Gould praised most of Wilson’s sociobiology, but he rejected what he saw as biological determinism in humans. He and others argued that there is no evidence for specific genes that determine human behavior and believe the theory of such genes is not testable.19 Some others carried the concept of genetic control of human behavior further than Wilson did.
One must recognize that evidence does exist for genetic control of behavior in non-human animals. These changes could be epigenetic changes rather than changes to the DNA.20 Consequently, even though much of human behavior seems to be modifiable by culture, the possibility that significant genetic control of behavioral tendencies exists in humans needs to be considered. If such control exists, the strong possibility, perhaps certainty, follows that mutations could alter that behavior. With random genetic damage of genes occurring, it would be difficult to escape the conclusion that some human behaviors can be altered or eliminated by mutations and would be subject to the processes of natural selection, including kin selection. Does this mean that sociobiological explanations of human behavior are correct? What does that say about morality?
Some sociobiologists emphasize that sociobiology does not try to indicate what our behavior ought to be, but others do claim that sociobiology determines what we should do. Psychologist Plutchik recommended that human emotions are best understood in the context of the history of their evolution from other animals and asserted that this view of emotions will benefit clinical practice in psychology.21 Some ethics textbooks explicitly base their system of ethics on the principles of sociobiology. Alexander concluded that conscience is “the still small voice that tells us how far we can go without incurring intolerable risks. It tells us not to avoid cheating but how we can cheat socially without being caught.”22
Concepts of right and wrong for Christians are understood as a moral code given to humanity. The Ten Commandments and the teachings of Christ have provided a standard for human behavior. Clearly, humans do not follow that standard very well. The apostle Paul lamented: “For I do not do the good I want to do; no, the evil I do not want to do—this I keep on doing” (Rom. 7:19, NIV). Perhaps we have fallen so far from our original created condition not only because of temptations to sin, but also partly because mutations have affected our behavior. Perhaps both humans and non-human animals were created with well-balanced behaviors as well as morphologies that since have undergone generations of change driven by mutations or epigenetic influences and natural selection. As a result, part of human character reflects this change, and that has emphasized the selfish side of human nature.
The view presented here differs from current evolutionary thinking by proposing that the basic process of kin selection and its effect on inclusive fitness have operated only within humans and within other created groups of organisms. It has not carried behaviors from one such group to another, since these groups have not evolved from common ancestors. Christians also accept by faith (and by reasoning that is at least logical, even though not scientifically testable) that humankind is not biologically destined but has a measure of free will to seek the ability from God to act in ways that are truly altruistic and not just the result of gene modification and biological determination.
Does genuine altruism exist in humans? Observations of human behavior make it difficult to believe that some behavior is not truly altruistic, because abundant examples of human altruism can be documented.
An Interventionist View of Sociobiology
According to interventionist theory, the original animals had the greatest level of complexity in their behavior, and the interspecific and intraspecific interactions between organisms were the most finely tuned and harmonious at the beginning of life on Earth. Potential conflicts among animals over the division of territory and other resources were originally settled by non-damaging conventional displays like those still common in a number of animals. Examples include the male rattlesnake wrestling matches and the lizard tail lashing or head-butting “battles.”
True altruistic behavior may have been much more common. Perhaps, originally, subadult animals commonly assisted their parents in raising the next brood or litter. Population-control mechanisms were also much more finely tuned than at present. Behavioral mechanisms for maintaining a stable ecological balance were built into the animals’ genetic makeup as part of an ecological system that originated through intelligent design rather than chance.
The instinctive behavioral mechanisms that prevented damaging conflicts were not originally subject to random mutational changes. Because of adequate protection from mutational damage, individuals with these behavioral mechanisms would not be subject to unfavorable competition from individuals who would benefit from “cheating.” With the introduction of random mutations and defects in repair processes, these behavioral mechanisms began to break down. Epigenetic responses to conditions in the changed world after sin may have been important.
Natural selection and, especially, kin selection have acted to slow this breakdown. The altruistic behaviors that have survived the negative effects of mutation are primarily those that have been preserved by kin selection and increase the inclusive fitness of the organism. When mutations began to cause the loss of some of the original created behavior patterns, natural selection would determine whether the original type or the mutated type would become most common. If mutations in a female bird removed the original pattern of helping her parents raise their young and she built her own nest, she would likely produce more young in her lifetime than others who began reproducing later. (This is the same result that would be expected by naturalistic theory.) As a consequence, the “non-helper genome” would become more common and eventually replace the “helpers.” On the other hand, in some situations, the genes for “altruistic” behaviors are favored by kin selection. Consequently, they continue to be common in the population. The Florida scrub jay lives in a situation in which the young are not likely to reproduce successfully the first year. Consequently, their inclusive fitness is increased if they help their parents raise young that share many genes that they also have. Thus, kin selection favors retention of the “altruistic” behavior in this environment.
An intelligent and benevolent Designer could choose to invent an ecological system with a balance of nature based on harmony rather than on competition. In contrast, mutation and natural selection have no ability to look at the “big picture” and see what is best for the overall ecological balance. Natural selection is strictly shortsighted—it favors any change that increases successful reproduction. The ultimate result of the rule of natural selection is the competitive, vicious side of nature. Humans are not captive to behavior resulting from a mutated nature, but can seek aid from our Creator to grow in moral strength and live unselfish and responsible lives.
Leonard Brand, Ph.D., is Professor of Biology and Paleontology and former Chair of the Department of Earth and Biological Sciences at Loma Linda University in Loma Linda, California, U.S.A.
Arthur Chadwick, Ph.D., is Professor of Geology and Biology at Southwestern Adventist University, in Keene, Texas, U.S.A.
For more on this topic, see the peer-reviewed “Sociobiology: Why Do Humans Behave as They Do?” by Leonard Brand and Joe Galusha in The Journal of Adventist Education 74:2 (December 2011/January 2012): 23-27: http://circle.adventist.org/files/jae/en/jae2011 74022206.pdf.
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