Indirect Benefits of Altruism
The different benefits gained by altruists that are received from individuals other than the original recipients of the act.
Traditionally, two theories have mainly been used to explain how altruistic behaviors between organisms can be adaptive, and these are kin selection theory where individuals aid those with which they share a number of genes (Hamilton 1964) and reciprocal altruism where individuals aid others who can and will return the favor in the future (Trivers 1971). These have been mostly adequate in explaining a vast amount of altruism, particularly in nonhuman animals. However, when it comes to humans, there exist a number of examples of altruistic behaviors that neither genetic relatedness or reciprocity can explain. These include giving to various charities (e.g., overseas causes, animal sanctuaries), donating blood or bone marrow, and risking personal safety to save others (e.g., rescuing a puppy from a burning building). As such examples are not unusual, this contribution will explore how such altruistic acts can still be adaptive in terms of increased survival and/or reproductive success, by showing how their costs are balanced by other benefits that the altruist receives.
A previous attempt to explain altruism was that it was somehow beneficial for the group, a theory that was all but abandoned in the latter half of the twentieth century. However, a more recent theory of how altruism could have evolved to indirectly benefit groups has been put forward, named multi-selection (e.g., Wilson and Sober 1994; Wilson 2015). According to multi-level selection, natural selection can act on not only an individual but also on a group level. More specifically, even though altruistic members within a group can be outcompeted by selfish members, if the overall fitness of the group is increased by having altruistic group members, then this will be selected for. This can occur in particular circumstances, and the concept of what constitutes a group can vary between levels of organization.
This builds on the original suggestion of Trivers (1971) that reciprocity is the benefit an altruist receives. However, whereas reciprocal altruism concentrates on the recipient of the act returning the favor, indirect reciprocity (Alexander 1987; Nowak and Sigmund 2005) states that another individual or third party will return the act to the altruist. This process can work when altruistic acts are reliably and widely broadcast to others in a group, so is highly possible in a social species such as humans who live in groups. As such, a number of contemporary theories have been put forward that show how indirect reciprocity can work and also what specific benefits it provides to the altruist, which are discussed below.
Image scoring (Nowak and Sigmund 1998) attempts to explain the mechanism by which indirect reciprocity can evolve. Using a theoretical model, they suggest that every individual in a group has an “image score” that relates to their previous altruistic interactions with other members of a group. This is based on group members interacting repeatedly with different individuals in the group in pairs for one-off interactions (i.e., without interacting with that individual again) where one member of the dyad can choose to help the other individual or not. If they choose to help, they have a score of one added to the image score, but if they choose not to help they have a score of one subtracted from their image score.
Therefore, being altruistic in these interactions can increase an individual’s image score which can be beneficial in future interactions. This is because, according to Nowak and Sigmund, individuals in the new dyads will base decision on whether or not to help their new partner on their own “threshold” for image scores. In other words, each individual will have a personal numerical value of image score that a partner must have or exceed for them to decide to help. Any partner in an interaction who has an image score below this threshold will therefore not be helped. So, as receiving help from others can be beneficial, a higher image score is adaptive as it means an individual is more likely to pass a new partner’s threshold and thus provide help. Therefore, this theoretical model provided by Nowak and Sigmund (1998) can show how indirect reciprocity can evolve in groups such as humans.
Competitive altruism (Roberts 1998) similarly uses a theoretical model of how indirect reciprocity can evolve. He suggests that cooperation among group members is a two-stage process, with an “assessment” stage followed by a “partnered” stage. The partnered stage involves individuals in a group forming long-lasting partnerships where they engage in repeated cooperative interactions with each other. Therefore, as Roberts (1998) suggests, it is important to ensure that a cooperative partner is gained in this second stage.
Furthermore, Roberts suggests that there is an active choice of partners for this second stage (i.e., individuals are able to choose who they have as their partners). As a result of this, individuals will compete with one another to increase their displays of altruism in the assessment stage so that they are a desirable partner. According to Roberts, this then leads to assortative matching whereby the most cooperative individuals will pair together, followed by the next most cooperative, and so on. If altruism in the assessment stage is an honest signal of altruism, then the most cooperative pairs will benefit the most in the partnered stage through their future interactions.
Although the original theory is based on hypothetical models, additional empirical research has shown that humans do indeed follow the principles of competitive altruism when available. In a study where participants first interacted with one another in a cooperative group game (i.e., an assessment stage), those that had behaved most cooperatively in the game were more desired as partners in a further stage where participants cooperated in pairs, and actually benefited more overall (Sylwester and Roberts 2010).
The idea of altruistic punishment (Fehr and Gachter 2002) is that individuals within a group will cooperate with other group members, as non-cooperation is punished by other group members. This punishment would be severe to act as a deterrent, but will also be costly to perform (i.e., certain group members will incur the costs of punishing non-cooperators even if they themselves do not benefit). Fehr and Gachter show this empirically in a study using the public goods game, where participants can contribute to a public good so that all group members can benefit. However, as often happens in continuous rounds of this game, individuals stop contributing to the public fund but still get the benefit from those that do contribute. Fehr and Gachter (2002), however, introduced between rounds the opportunity for group members to punish those that had not contributed and found that this was a deterrent that led to those punished individuals to return to contributing, thus ensuring in future rounds that cooperation to the public fund was maintained.
This was found even though it was costly to punish others (although the cost of punishing was less than the cost of being punished), meaning that punishers were behaving altruistic. So what is the motivation to punish, when it is costly and you do not directly interact again with the individual you punished? Fehr and Gachter state a proximate explanation for this, in that we feel strong negative emotions of anger when exposed to non-cooperation (i.e., cheating). Furthermore, the potential costs of punishing may be quite low if minimal punishment is needed to ensure individuals continue cooperating within a group (i.e., potential non-cooperators are aware of the costs they could incur). Therefore, these findings suggest that potential punishment from others may have been important for indirect reciprocity within a group to be adaptive.
Altruism as a Costly Signal
The reason why altruistic acts can provide indirect benefits to the altruist via an enhanced reputation is due to such acts being costly (Gintis et al. 2001). As a result, these costly acts can signal to others that the actor may be an able coalition partner, potential competitor, or mate. This works on the premise that costly signals of altruism are honest, meaning that they are directly related to the underlying quality of the individual and that they are a handicap (Zahavi 1975). Furthermore, they must also be effectively broadcast to others, beneficial to the receiver and the actor, and a reliable indicator (Eric Alden Smith and Bliege Bird 2000).
An example of how altruism as a costly signal can provide indirect benefits can be seen in the practice of turtle hunting among the Meriam in Australia (Bird et al. 2001). Hunting of turtles is difficult and risky, so can act as a reliable signal of a hunter’s underlying qualities. Therefore when successful, turtle hunters share the catches with all members of their group in large public feasts, instead of keeping it to themselves. This seemingly altruistic act therefore acts as an effective costly signal, as it is a reliable indicator of their ability, a handicap (as the hunter is incurring the cost of giving away their catch), effectively broadcast to other group members and beneficial to the altruist (allows them to display their quality) as well as the receivers (who gain reliable information about the hunter and free turtle meat). As a result, these hunters reap the indirect benefits of increased social recognition and reproductive success (Smith et al. 2003).
Altruism and Mate Choice
Finally, a number of studies have recently explored the possibility that being altruistic provides indirect benefits in mate choice settings. This follows from the view that altruism can be a costly signal, as it can be then used to attract mates by reliably displaying desirable traits to potential mates (as happens with turtle hunters among the Meriam). As a result, it has been shown that individuals will behave altruistically in the presence of potential mates (Bhogal et al. 2016; Farrelly et al. 2007; Iredale et al. 2008; Tognetti et al. 2012, 2016), and also that being altruistic makes individuals more desirable to potential mates (Barclay 2010; Farrelly 2011, 2013, 2016; Moore et al. 2013; Oda et al. 2013; Phillips et al. 2008). Furthermore, there is real world evidence of the indirect benefits in mate choice that being altruistic can bring, as single individuals who are altruistic are more likely to be in a long-term relationship 1 year later than those that are not (Stavrova and Ehlebracht 2015).
As new research into the indirect benefits of altruism built on traditional explanations of how altruism can be adaptive, we now have a much richer and detailed understanding of all examples of altruistic behaviors and acts that occur in the real world. Although there are different perspectives on how these indirect benefits manifest themselves, what is clear is that the role of enhanced reputation of the altruist is what underlies them. As such, it provides a useful lens through which to view human altruistic acts such as charity, heroism, and generosity amongst others. When understanding that the ultimate explanation for such acts is increased reputation (which in turn can lead to increased survival and/or reproductive success), their origins and motivation become clear. Although this may be a cynical way to view human altruistic acts, it should not ignore the fact that by being “altruistic” is at the heart of our nature as a highly social species.
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