Table of Basic Ideas Related to Evolutionary Psychology

System Level:

Individual

Problem:

How to survive?

The bodies and minds of organisms are made up of evolved adaptations designed to help the organism survive in a particular ecology (for example, the white fur of polar bears).

System Level:

Dyad

Problem:

How to attract a mate and/or compete with members of one's own sex for access to the opposite sex?

Organisms can evolve physical and mental traits designed specifically to attract mates (e.g., the Peacock’s tail) or to compete with members of one’s own sex for access to the opposite sex (e.g., antlers).

In most species, the effects of sexual selection are seen in males since they typically have a faster reproductive rate than do females.

System Level:
Family & Kin

Problem:

Gene replication. How to help those with whom we share genes survive and reproduce?

Selection occurs most robustly at the level of the gene, not the individual, group, or species. Reproductive success can thus be indirect, via shared genes in kin. Being altruistic toward kin can thus have genetic payoffs.

Also, Hamilton argued that sexual reproduction evolved primarily as a defense against pathogens (bacteria & viruses) to "shuffle genes" to create greater diversity, especially immunological variability, in offspring.

System Level:
Non-Kin Small Group

Problem:
How to succeed in competitive interactions with non-kin? How to select the best strategy given the strategies being used by competitors?

The two sexes often have conflicting strategies regarding how much to invest in offspring, and how many offspring to have.

Parents allocate more resources to their offspring with higher reproductive value (e.g., "mom always liked you best"). Parents and offspring may have conflicting interests (e.g., when to wean, allocation of resources among offspring, etc.).

Problem:

How to succeed in competitive interactions with non-kin? How to select the best strategy given the strategies being used by competitors?

Game Theory / Evolutionary Game Theory

Organisms adapt, or respond, to competitors depending on the strategies used by competitors. Strategies are evaluated by the probable payoffs of alternatives. In a population, this typically results in an "evolutionary stable strategy," or "evolutionary stable equilibrium" -- strategies that, on average, cannot be bettered by alternative strategies.

Problem:

How to maintain mutually beneficial relationships with non-kin in repeated interactions?

One can play nice with non-kin if a mutually beneficially reciprocal relationship is maintained across multiple social interactions, and cheating is punished.

Non-Kin, Large Groups Governed by Rules / Laws

Problem:

How to maintain mutually beneficial relationships with strangers with whom one may interact only once?

(Also called "strong reciprocity"). One can play nice with non-kin strangers even in single interactions if social rules against cheating are maintained by neutral third parties (e.g., other individuals, governments, institutions, etc.), a majority group members cooperate by generally adhering to social rules, and social interactions create a positive sum game (i.e., a bigger overall "pie" results from group cooperation).

Generalized reciprocity may be a set of adaptations that were designed for small in-group cohesion during times of high inter-tribal warfare with out-groups.

Today the capacity to be altruistic to in-group strangers may result from a serendipitous generalization (or "mismatch") between ancestral tribal living in small groups and today's large societies that entail many single interactions with anonymous strangers. (The dark side of generalized reciprocity may be that these adaptations may also underlie aggression toward out-groups.)

Capacity for generalized altruism, acting like a "good Samaritan," cognitive concepts of justice, ethics and human rights.

To out-group members:

Capacity for xenophobia, racism, warfare, genocide.

Problem:
How to transfer information across distance and time?

Genes are not the only replicators subject to evolutionary change. “Memes” (e.g., ideas, rituals, tunes, cultural fads, etc.) can replicate and spread from brain to brain, and many of the same evolutionary principles that apply to genes apply to memes as well. Genes and memes may at times co-evolve ("gene-culture co-evolution").