The Selfish Gene: Chapter 7 Summary & Analysis

Many people consider parental altruism to be a separate from kin altruism in general. They often consider parental care to be an extended part of reproduction. Dawkins disagrees. He would rather think of things in terms of strategies for “bearing” new children, and “caring” for existing children.

Decisions in general entail choosing how to use one’s energy. “Caring” decisions involve choosing how often to feed one’s child, based on its “degree of relatedness” to oneself and its overall chances of survival. “Bearing” decisions involve choices like using one’s energy to mate. Sometimes, caring and bearing decisions compete with each other, for example, when one wonders if one should care for an existing child or bring another into the world.

Dawkins thinks that, depending on the species, different combinations of caring and bearing will be evolutionarily stable strategies. The only strategy that will not be stable is a “caring only” strategy. If every animal in a species spent all its energy caring for existing animals instead of mating, then no new animals would be born, and the species would die out.

Mammals tend to invest in “caring” strategies. Decisions to bear a new child are often followed by decisions to care for that child, and parents tend to choose feeding their children over other relatives. From a genetic perspective, both one’s brother and one’s child both share half of one’s genes, so it shouldn’t make a difference which one a person feeds. However, since “caring only” strategies don’t fare well in the gene pool, and one didn’t give birth to one’s brother, one is still more likely to feed one’s child.

Wynne-Edwards thinks that animals deliberately reduce their birth rates as a form of altruism to the group at large.  Dawkins disagrees. He thinks it’s an attractive hypothesis, since it’s good advice for humans, otherwise we’ll run out room on the planet.  Nonetheless, he thinks actually, predators, disease, and starvation keep things in check (with the exception of humans, who rarely get hunted any more). In fact, Dawkins agrees with Wynne-Edwards that animals regulate their birth rates—he just disagrees about why they do. Wynne-Edwards thinks animals do it because they are altruistic toward the group, but Dawkins thinks there are underlying selfish reasons. 

Wynne-Edwards gives three reasons to support the idea that population control is altruistic in animals. First, animals often fight over territory. Losers usually don’t breed, presumably so that stronger “winners” can breed and benefit the group as a whole. Next, animals also often have dominance hierarchies. Those low in the social order similarly avoid breeding. Finally, animals have “epideictic displays,” meaning they swarm or flock as a group. Wynne-Edwards thinks epideictic displays enable group members to estimate their population size and avoid breeding when the swarm is overcrowded, all for the good of the group as a whole. 

In contrast, Dawkins wants to show that when animals don’t breed as much as they could, it’s because of their “selfish" genes. In order to do so, Dawkins references David Lack, who researches “clutch” (or flock) sizes in wild birds. Lack argues that birds have an “optimal clutch size.” Although each bird could lay as many eggs as possible, many don’t. This is because more energy spent “bearing” means less energy available for “caring.” So, there must be a ratio of bearing to caring that maximizes number of surviving children overall. This is the optimal clutch size. Wynne-Edwards thinks it’s the clutch size of the group overall that’s optimized. But Lack thinks each bird is choosing the clutch size that maximizes her own offspring.  

For example, a bird that lays four eggs has to divide up the available food between four chicks, but her neighbor, who only has three chicks, can give each chick more food. It could easily turn out that the neighbor keeps all her three chicks alive, but the bird with four chicks is only able to keep her two strongest chicks alive. Dawkins believes that even though it looks like birds are being altruistic for the good of the group when they lay fewer eggs than they can, they are really trying to maximize the number of surviving offspring they have, which is a selfish motivation.

Put another way, natural selection adjusts the initial clutch size according to available resources in the environment. Individuals who are prone to having too many children keep fewer children alive, meaning they have fewer grandchildren, and fewer genes in the gene pool overall. The individuals inclined toward having just enough children (to maximize survival chances given available resources) will be favored by natural selection.

Dawkins thinks that Lack’s theory can explain all the examples Wynne-Edwards discusses. For example, it seems like birds who lose fights and fail to secure territory are being altruistic toward the group by not breeding. However, their best strategy might be to wait until a bird with territory dies and swoop in on the vacant territory, because they know they’re bad at winning territory by fighting for it. Similarly, animals who are low in the pecking order might be waiting for their optimal chance to breed (rather than holding back for the good of the group). Dawkins thinks what looks like altruism can once again be explained by selfish motivations.

Dawkins agrees with Wynne-Edwards that “epideictic displays” (like swarming) might be a way of estimating population size. But Dawkins’s story deviates from there. Imagine that starlings can estimate the population of starlings in an area, and lay fewer eggs in seasons when competition for food will be greater. From a selfish perspective, it would then also make sense to trick other starlings into thinking the population is denser than it actually is (so that the others lay fewer eggs, leaving more resources available). Maybe epideictic displays (like flying around in a swarm, or chirping loudly in unison at sunset) are ways to trick others into thinking the group is denser than it actually is.