Unit 07

Why did humans evolve the potential for good and evil?

Much of the philosophical debate surrounding evil is a question of human nature…Are humans, as a species, inherently capable of evil?  Are we predisposed to it?  Is it unavoidable?  The answers to these questions might be informed by the science on how life (and our human brains) evolved to maximize survival and reproduction, especially among species that live within social groups.

07-A: What is Natural Selection?

• How do the fundamental principles of sociobiological theory (also known as the theory of evolution) offer an explanation for the psychological phenomenon that we observe today in humans and other creatures?  In your response, be sure to address...

  • • How is "natural selection" defined in the context of both survival and successful reproduction?

    • What kind of "adaptations" might influence the fitness of an individual creature, both in terms of its physical characteristics as well as its psychological predispositions (preferences, instinctual behavioral, cognitive capabilities, etc.)?

    • How can we describe evolution in the context of mutations, genetic variance, and heritability?

• Define and provide examples (for several different species) of

  • • Intrasexual competition

    • Intersexual selection

To understand the role of evolution in evil we first have to understand the fundamental principles of the theory.  

READ: Darwin, Evolution, & Natural Selection

Reproductive success is a key factor of natural selection. It determines which traits will be passed down to offspring, and these heritable traits can either increase or decrease the fitness of the organism. Therefore, sexual selection, or how an organism chooses potential mates, is a major determinant of which traits are passed down to the next generation. 

The things that affect survival odds seem rather intuitive... can you stay alive in your environment, can you get enough to eat, and can you avoid any predators that consider you food?  But as has already been established, surviving is not enough, so there's another powerful force at play... sexual selection.

When you watch the next video, note we'll use slightly different terms than those they use to explain the concepts:

• "Male competition" is more broadly considered intrasexual competition

• "Female choice" is more broadly considered intersexual selection

07-B: The Evolution of Evil

• What are fitness costs, and how are they inflicted on others?  Be prepared to offer examples of direct and indirect costs that one member of a species might inflict on another member, or on an entire group.

• What were the potential fitness benefits that the capacity for committing homicide provided?

• What anti-homicide mechanisms constrained killing to the situations where it was uniquely beneficial?  In other words, why didn't the human species evolve into a senseless pack of homicidal maniacs that try to kill everything that moves?

• How did biological differences in sexual reproduction between male and females lead to different circumstances in which they would commit infanticide?

• What does it mean to talk about costs to inclusive fitness, and what examples can you offer that help explain the inclusive fitness costs of homicide?

• Why did homicide and anti-homicide co-evolve?

If fitness increases the odds of survival and reproduction, imposing a fitness cost means that an individual organism is doing something that reduces the likelihood of another living and passing on its genes.  The most direct and costly is killing someone, especially before they have ever had the opportunity to pass their genes on to the next generation.  However, there are many ways in which one individual might indirectly harm the odds of other's chances to survive and reproduce.  For example, if you hoard resources like food and water to ensure you have more than you need, there is less available for others and some (or their children) may get sick or die.

The big picture idea here is that the human species evolved the capacity for doing things we now regard as evil because, under certain conditions, those evil things increased the likelihood of survival and reproduction for an individual and its genetic offspring.  Now, let's look in detail on how evolution might have favored psychological mechanisms for inflicting fitness costs on others in order to increase an individual's probability of surviving, reproducing, and passing the same potential on to the next generation.

One note before you start reading the next resources, the word "kin" refers to relatives and those with whom you have close relationships with.  The term "conspecific" is used to refer to a member of the same species that does not have any particular relationship with you.  So, think strangers... in other words, no one of a specific relation, just another human.

OPTIONAL: Read Buss' essay on The Evolution of Evil for more on why it is dangerous, but still correct, to argue that the potential for evil is part of human nature.

07-C: If You Died Tomorrow....

• What is mortality salience and how does terror management theory predict it should affect us? 

  • • What is the research that demonstrates this relationship?

• How might we conceptualize the evolution of ideology (a.k.a., religion) as an adaptive mechanism with the specific advantages that it would provide to the inclusive fitness of a group?

  • • How does this relate to recent neuroscience research?  What area of the brain seems to be involved, and how did researchers demonstrate this?

READ: Mortality Salience

07-D: Altruism

• Define altruism and provide a fitness-based argument for why a genetically inherited predisposition for engaging in it was selected for.  Consider:

  • • Kinship

    • Reciprocal altruism

    • How inclusive fitness influences the probability of genetic traits being passed on

• How is altruism demonstrated in rats?  Who benefited?  How does a rat's social experience affect their altruistic behavior?

READ: Rats show kindness towards strangers, a new study shows (also in Files section of Canvas)

How likely are you to help someone who looks different than you? Are you more likely to help an in-group or out-group individual? Does social experience determine one's propensity for altruistic behavior? Researchers at the University of Chicago examined these and other questions in their experiment on rats' social experience and helping behavior.

Closing Thoughts...

It is always important to remember a point made earlier in one of the resources -- what evolved is what was advantageous to survival and reproduction at an earlier time.  The circumstances which shaped evolution are not necessarily the same in which we live today, and no species evolves for what comes next... only what currently happens to be.  Thus, we can explain the existence of evil in the context of how it may have helped the species survive and reproduce without suggesting that it is therefore inevitable, necessary, or justified today.  Nonetheless, it is a useful exercise to ask yourself what you believe in, and then to consider how those beliefs might have been selected for by evolutionary pressures in the same way that the shape and function of your hands evolved to serve an important and complex function.

If you're interested in learning more...