After Charles Darwin’s “On the Origin of Species” came out in 1859, the book caused a lot of buzz in the field of evolutionary biology. Darwin’s theory of Natural Selection created many other questions in animal behavior. Today, the development of genetics has led to a better understanding of the causal factors as well as the results of many facets of animal behaviors. The understanding about why social animals behave the way they do, has been recently accounted upon by many other theorists. Freeman and Herron in 2007 discussed the types of social interactions in “Kin Selection and Social Behavior”, and tallied as follows:
Actor benefits-Cooperative
Actor is harmed-Altruistic
Recipient benefits-Selfish
Recipient is harmed-Spiteful
Among the many social behaviors of animals which affect the state of fitness of the organisms involves the behavior of altruism. Altruism is simply understood as an act of helping others while facing a visible disadvantage. The benefactor supports the recipient of the benefit at the stake of its own fitness. Since altruism is mostly common in social animals, I will be using examples from researches done on social animals to discuss different perspectives of altruism.
I. What is altruism?
Evolutionary Biology view
Biological altruism can be defined as an act of benefiting another organism with a cost of fitness to the benefactor. The benefits and costs are measured with respect to reproductive fitness. An organism which behaves altruistically reduces the number of offspring it is likely to produce itself, but boosts the number that other organisms are likely to produce (Stanford Encyclopedia of Philosophy, 2003, 1). For example, an experiment carried out in 126 wild immature and adult turkeys showed that the dominant wild turkeys were helped by their subordinate turkeys in choosing mate for reproduction. The result was that the dominant male turkeys produced comparatively higher number of offspring than the solitary male turkeys. They mated with significantly more females, while the subordinate turkeys did not mate or perform fatherhood (Krakauer, 2005). Because the subordinate turkeys did not reproduce, and helped other turkeys to pass their genes to the next generation, they are said to perform altruistic behavior in Evolutionary Biology.
Natural Selection is considered the key to Evolutionary Biology. However, the prosocial behavior of helping others without any beneficial incentive is an irony on what Darwin’s theory of Natural Selection is primarily based on. Under Natural Selection, an individual competes among and beyond its group circle to survive and reproduce successfully. So selection should leave behind the ones that are unable to compete. The altruists who help others and risk their own life by decreasing their Darwinian fitness (ability to survive competition and reproduce) should not be able to continue to the next generation. In other words of selection, altruistic organisms should have disappeared in their early stage of evolution due to competition for survival of the fittest. But the prevalence of altruistic animals in nature is a contradiction to what Darwin had laid down in his book about the origin of species.
Hypotheses and theories proposed in the past
Charles Darwin (The Descent of Man)
At first, Darwin’s theory of Natural Selection had trouble explaining the existence of altruism in nature. But he later discussed in his “The Descent of Man” (1871) that altruism can be defined by natural selection as he quotes, “a tribe including members who…were always ready to give aid to each other and sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection”. He thus was able to explain altruism in the language of natural selection where altruistic behavior can be explained through group selection. Because competition does not only prevail among individuals but also among groups, helping group members through self-sacrifice can increase the sustainability and domination of the group. One can go as far as sacrificing life for the benefit of the group. In fact, selection demands altruistic behavior from the group members when there is a danger for the group. For instance, Belding’s ground squirrels are well-known for alarm calling whenever they see the threat of predation. Generally, the squirrel which gives the alarm is in a greater risk of predation than the other group members (Sherman, 1985). This phenomenon is called group selection which will be discussed later in the paper.
Hamilton’s rule (1964)
William D. Hamilton designed a mathematical equation to explain the altruistic behavior among relatives in social animals. He clarified how selection can favor traits that result in decreased personal fitness if they increase the survival and reproductive success of close relatives (Freeman and Herron). Since the altruistic behavior is discriminatory and is limited to relatives only, selection makes sure the altruistic gene to passes to next generation. Hamilton formulated the term the coefficient of relatedness, r which compared the probability of genetic similarities shared due to shared ancestry. Hamilton used B for the benefit gained by the recipient and C for the cost to the benefactor. Hamilton’s rule thus states that altruism occurs if the product between benefit and the coefficient of relatedness exceeds the cost faced by the altruist. The mathematical representation for an altruistic interaction would be as follows:
Br>C
Although Hamilton’s rule has not been proved practically in nature, it helps us understand how relatedness can affect the helping behaviors in the nature which is known as the theory of kin selection. Kin selection will be accounted upon later in the paper.
Maynard Smith (1964)
John Maynard Smith first developed game theory to explain the economic behavior in humans. He later used his theory to analyze the helping behavior in social animals. Game theory is about the strategy used by organisms to determine how to behave in a competitive interaction without having complete information about the opponent as well as the consequence of the action. Hence, according to Smith, an altruistic act in nature would be carried out in order to reduce loss and increase the net benefit after an interaction (Ficici and Pollack, 2007).
Thomas Hobbes (1650)
Thomas Hobbes (1588-1679) was the first person to relate altruism with psychology. Psychological perspective of altruism is only applicable to human beings. Moreover, Hobbes stated that human nature is always motivated by self-interest and that it is self-preservation that makes humans social (Millen, 2006). In the words of Hobbes, being social in human sense is to conform to the society in order to reduce the risk of isolation and punishment. Hence, Hobbes concluded that humans do not have any intention to bring about greater good for the society by being social. It is rather a selfish interest which ends up benefiting the society in the long run.
II. Types of Altruism
Group Selection
Conspecific altruism refers to the altruism in which both the benefactor and the recipient of the benefit belong to the same species. Group selection is a type of conspecific altruism which takes place when an individual acts altruistically for the betterment of the group. It is evident that survival and reproduction are not random and are tied to individual variations (Freeman and Herron). But the theory of group selection proposes that individual variations do not matter in selection when it comes to the survival of the group. Hence under group selection, an individual acts in the interest of the group while the affect of the action in the fitness of the individual is relatively unimportant in selection.
However, group selection has faced a lot of criticism because altruism can be beneficial in the group level while the altruists can be exploited by other non-altruistic members of the group. This can probably lead to the extinction of the altruistic allele from the group due to the survival of the fittest. Even if a group is composed exclusively of altruists, all behaving nicely towards each other, it only takes a single selfish mutant to bring an end to this happy idyll (Stanford Encyclopedia of Philosophy).
Kin Selection
Hamilton clarified how selection can favor traits that result in decreased personal fitness if they increase the survival and reproductive success of close relatives (Freeman and Herron). This kind of animal behavior is called kin selection. It involves an individual helping its relatives while risking its own survival for selection to favor the succession of the species. Hamilton further stated that though an animal reduces its own fitness by helping its relatives, it increases the inclusive fitness. According to Hamilton, inclusive fitness of an organism is its personal fitness and the sum of its weighted effects on the fitness of every other organism in the population. The effects of the helping behavior on the fitness of other organism are determined by the coefficient of relatedness (Stanford Encyclopedia of Philosophy).
Kin selection can also take place in the form of blood kinship. According to the theory of blood kinship, altruism can be defined by the phenomenon of organisms helping their kins who are genetically related. By helping their group members related by blood, the organisms are protecting their own genes to be passed to the next generation assuming that a gene pool consists of similar copies of genes. As a whole, altruism helps in the continuity of the alleles that are shared by blood relatives. Kin selection holds that risking one’s fitness to benefit the fitness of relative can indirectly help preserve the likelihood of passing on the gene to the next generation (Callahan, 1994).
Reciprocal Altruism
According to De Wall (2005), reciprocal altruism presupposes that:
a) The exchanged acts are costly to the donor and beneficial to the recipient;
b) The roles of donor and recipient regularly reverse over time;
c) The average cost to the donor is less than the average benefit to the recipient,
d) Except for the first act, donation is contingent upon receipt.
Studies on reciprocal altruism show that help is provided to those individuals which had been helpful in the past or show signs of being helpful. However the idea of kin selection does not fully agree with the argument that altruists expect help back. A study on male bonnet macaques as discussed in J. Silk’s “The Patterning of Intervention among Male Bonnet Macaques: Reciprocity; Revenge, and Loyalty” tended to show that they show altruism to those individuals who had been helpful in the past with a tendency to balance the act of receiving and giving help. The research was done on 70 male monkeys (bonnet macaques) which were studied for their social behaviors.
The results showed that the monkeys stopped helping other monkeys who failed to reciprocate, hence showing a relationship between reciprocity and altruistic behavior. The research provides good information on how primates form social relationships by discriminating in helping behavior. In addition, reciprocal altruism takes place in kin-specific as well as non-kin interactions which questions kin selection. For example, altruistic behavior such as grooming in Japanese Macaques can take place in non-kin individuals too. But help is always expected back in the future (Schino, di Sorrentino and Tiddi, 2007).
Moreover, proper assessment of kin selection helps us to determine whether the helped individual is expected to help back in the future or not. In an experiment, the researchers, Richardson, Komdeur and Burke (2003) tried to show that cooperatively breeding female Seychelles warbler (Acrocephalus sechellensis) help other subordinates to raise new nestlings only if they had been helped by the subordinates or the siblings who shared the same nest and fed the other siblings in the past. The results showed that subordinate-nestling relatedness had a direct relationship with the helping behavior of the subordinates. The experiment also helps understand the discriminatory helping systems in aves. However, reciprocal altruism seemed to come into play in the experiment even if kin selection was also a major factor to affect the altruistic act.
Reciprocal altruism is not limited to relatives and can take place among individuals belonging to different kin and species. Maynard Smith proposed that reciprocal altruism can be successful only if there is a high probability that the individuals interact again (Ficici and Pollack). However, those individuals which are intimate to each other in regard of territory belong to the same species in general; and only relatives interact with each other more often in nature. Due to this fact, reciprocal altruism is very rare among organisms belonging to different species and genetically unrelated organisms.
III. Application of altruism
Altruism in humans
As discussed earlier, altruism, in psychological view, is unique to humans because they are the only ones that have cognitive development. Studying altruism in humans can help us better understand helping behaviors in other organisms because humans are social by nature and have a very competitive survivorship. Krueger, Hicks and McGue performed a research on twins in 2001 to find out the interrelationship between relatedness (genetic similarities) and personality. The researchers found out that altruism and antisocial behavior are independent of each other. In addition, they also found out that altruism and antisocial behavior have distinct etiologies. The study showed that altruism was related to positive personality while antisocial behavior was related to negative personality traits. This shows that both altruism and antisocial behavior are strongly associated with personality traits. Hence, it can be inferred that altruism in humans are largely affected by the environmental factor than genetic factor. The study done on twins helps understand the relationship among genetic similarity, environment and personality.
Another experiment done by Fehr and Rockenbach in 2003 tried to relate incentives and trust situations with the altruistic nature of humans in the form of sanctions. The experiment was carried out in 238 university students divided in different groups of investors which depended upon trust and incentive situations. Results showed that sanctions reduce altruistic behaviors while incentives such as rewards increased the pattern of altruism. The experiment successfully shows the nature of human cooperation in economic society and thus explains that altruism in humans is seen only in the presence of incentive for the benefactor.
Altruism in primates
Most of the social animals carry out behaviors that are beneficial to the welfare of the species they belong to and also to the species they do not belong. Warneken, Melis, Hanus and Tomasello (2007) conducted a research among chimpanzees and 36 18-month old human infants, in which all the subjects were genetically unrelated; and the subjects were fed well so that they do not inhibit the experiment with their natural characteristics of competition for food. 12 out of 18 chimps helped at least once as compared to 16 of 18 children tested who helped the experimenter in reaching his goal, in the first experiment. The only difference between them was that the chimps took a longer time to help because they were more mobile than the children which meant addition of time for them to concentrate in the condition they were subjected to. The second experiment also had similar result as of one. The third experiment however being different from the rest showed that chimpanzees help their conspecies without being motivated by any rewards. In addition, the experiment with controlled conditions also showed that the chimps also discriminated in acting to help in different circumstances. In other words, they helped whenever the help was fruitful.
Since the chimps are competitive in context of owning food, this study basically makes a clear argument with respect to earlier researches that when they are subjected to an environment with no hassle for food, they can show altruistic behaviors unlike humans who do not show helping behaviors without want and need of rewards.
IV. Criticism of Altruism
Psychological Egoism
Psychological egoism claims that helping behavior is shown by social animals for self-interest. The theory ignores the presence of true altruism in humans. A study done by Baumann, Cialdini, and Kenrick, in 1981 hypothesized that adolescents help others for self-gratification and the frequency of the act is highest when the individual is sad. The experiment was carried out to show that altruism does not depend on the urgency of help. It depends on the mood of the benefactor who helps the recipient of the benefit for self-satisfaction. Self satisfaction can be gained by positive change in mood, increase in reputation and the feeling of security due to the possibility of being helped in the future. Individual evaluation was conducted in regard of their primary response to certain mood. The experiment does not clearly argue about altruism being a prosocial behavior or an independent trait of selfish nature. However, the sample population was subjected to situations targeted to control the mood of experiment subjects which affect social behaviors of the study group. Since good mood increased the rate of helping behavior, the results suggests that altruism is performed for self-gratification and that altruism is related to mood. It can also be inferred from the experiment that feeling guilty and sad can positively affect the altruistic behavior of a person since the act of helping can be taken as a compensation for a wrong deed in the past rather than an obligation for the benefactor to help in the future.
Moreover, a number of researches in the past suggest that direct relationship with an altruistic person influences altruism in an individual. Accepting Hobbes’s theory that humans are altruistic because they are bound by conformity, an experiment was designed by Harris, Liguori, and Joniak in 1973 to find out if proximity with an altruist can motivate helping behavior in another person. The research was carried out in random men and women who were exposed to each situation in which they saw the act of altruism, aggression and indifference. Indifference was simulated by a control group which showed the subject of experiment an act of indifference to the exposed situations. The result was that no subject showed aggression to any of the three situations created while the act of altruism received a positive response. The research concluded that the rate of altruism is directly affected by the cultural view in helping another person. The result also showed that exposure to altruism affect the rate of altruism. Since people tend to be social (obey the rules) in most of the cases and value conformity, direct relationship with an altruistic person instigates altruism in the other person.
Compelled altruism
The stratification of reproductive fitness among some social insects questions the position of altruism in the context of reproductive fitness in which the workers are compelled to be sterile. The article, “Enforced altruism in insect societies” by Wenseleers and Ratnieks (2006) discusses the sanctions made by other members of a society in social insects which compel the workers to behave altruistically. The study was done on ten single-queen species, nine Vespidae wasps and the honeybee Apis mellifera. The researchers observed that the workers laid fewer eggs because the worker-laid eggs were policed by other members. Also, relatedness among the members decreased the effectiveness of the policy not letting the eggs develop into viable offspring. The research showed how social insects carry out compelled altruism in response to social sanctions done against their reproductive capabilities. It also showed how the insects practice compelled sanctions and how they discriminate sanctions depending on the coefficient of their relatedness. This example conflicts with the idea that social organisms carry out altruism driven by selection. Instead, helping behavior is shown by the insects because of direct pressure from the group members. At least, relatedness is seen to affect the intensity of sanctions imposed on the altruists which conforms with the idea of kin selection.
Altruism and Genetics
According to biologists, adaptation generally refers to a trait that affects the phenotype of the organism which increases its Darwinian fitness relative to individuals that do not have the trait (Freeman and Herron, 2007). The genes that carry the trait would then have more probability to get passed on to the next generation. This way, the gene that produces positive effects on the phenotype of an organism for better adaptation to the environment would favor another organism with the same gene because of selection. This is called the Selfish Gene Theory (Williams, 1966). Many biologists suggest that the selfish gene produces a phenotypic recognition so that the organisms which share the similar genes can interact and help each other easily. This occurrence is called the Green beard effect which suggests that, in a population of a species, an altruist recognizes another altruist by a specific trait which is the result of a single gene responsible for both the trait and altruistic nature of the species. Green Beard effect is related to kin selection. However, the theory has been criticized for the low probability of a single gene to affect both behavior and appearance.
While studying Green Beard effect, Jansen and van Baalen (2006) conducted an experiment whose purpose was to find out whether a single gene is responsible to affect both the recognition of altruism and altruistic character or there exists two different genes for the different traits. The game, Prisoner’s Dilemma, was used as a reference to find out the correlation among gene beard color and cooperation; and a simulation model was used to get the results. The researchers found out that the connectedness of a specific appearance and altruism in a gene is indirectly related to the average cooperation level in the targeted population. It meant that the lower the average cooperation level, the higher the beard color diversity since the lower cooperation level or the lower average pay off let the individuals with different beard colors to have different fitness levels only when beard color and the act of cooperation were related to each other. The researchers concluded that altruism may not be necessarily related to a gene responsible for a certain physical feature of an individual, but loose coupling between these two traits could be predicted. They also concluded there is a diversity of the genes which is responsible for both cooperative behavior and physical trait, and that the probability of the gene increases with the weakness in structure of the population. The researchers suggested that the gene which controls both phenotype and cooperative nature can not be the same for all organisms. The research seems to verify Green Beard effect to some extent.
V. Conclusion
The researches show that even if altruism is rare in nature, it is an integral evolutionary force prevalent in the nature. Though the idea of group selection has been criticized of its feasibility, organisms tend to act in such a way as to bring betterment for the group as a whole. Different theorists seem to have analyzed helping behaviors differently which are seen in natural environment of social organisms. After writing this paper, I have realized that group selection, kin selection and reciprocal altruism have their own importance in explaining altruism through different view points.
