Evolutionary Approaches

Ultimate and Proximate Explanations

We have already seen that there can be several levels of explanation for behavior
Explanations answer the question “Why?”
There can be many explanations, but usually, for any explanation, we can push back a level by asking “Why is that?” or "How does that work?"
Evolution (or some alternative) provides the “ultimate” explanation.

There are three forms of feedback based on consequences of behavior.
Learning depends on the impact of the outcome for the person.
Social institutions (broadly defined) depend on the impact of the outcome on the culture. This may include the effect of behavior on the rest of the environment.
Evolution depends on the impact of the outcome on the reproduction of the genes.

Note that environmental factors can modify the genes themselves on occasion.
The effect of behavior on the rest of the environment, beyond its impact on culture, can be significant - it may influence all three forms of feedback..

Why Does Evolution Occur?

A replicator is something that makes copies of itself, with occasional errors.
It produces some behavior, which has consequences that affect whether or not replication will occur.
Assume that there is some variability in the population of replicators - Some are more likely than others to reproduce.
Variation plus Selection equals Evolution
Genes are replicators. Are there others? Look up “memes”

Because of environmental pressures, there will be a gradual change in the make-up of the replicators, and hence in the species
Evolution has to work with very small changes to be sufficiently precise.
Natural selection: members of a species that do not survive long enough to reproduce to not pass on their genes
Sexual selection: when reproduction depends on sex, members that cannot find a mate will not pass on their genes

Evolution and the Selfish Gene

The gene-based view of evolution. The gene "wants" to reproduce.
“Want”, of course, is shorthand for “will continue to affect behavior in the species if and only if it reproduces”
The vehicle (the human) will have other desires, programmed by the genes, which have the effect of helping the genes.
E.g., desire for fats, sexual attraction

Evolution and Adaptation

Each species has evolved to solve the problems it needs to solve.
The specific skills tell us a lot about the environment in which evolution occurred.
Planning and problem solving are the unique skills that humans possess. They developed to enable humans to survive in their original environment.
The key to survival was an ability to deal with the complex structure of human society

“The Robot’s Rebellion” – Keith Stanovich
In humans, evolution does not try to program the species for every contingency
It passes on control to the person, and encourages problem solving
This leads to the robot’s rebellion: A clash between the goals of the individual and the goals of the genes that produced us

Can evolutionary psychological hypotheses be empirically tested or falsified?

It is not hard to invent “just-so stories” (Rudyard Kipling)
A testable hypothesis must make predictions about conditions under which a specific behavior is likely to be exhibited, and adaptive consequences of the behavior
(Predictions about stimuli, behavior, and outcomes)
Example: Proffet’s theory of pregnancy sickness

Don’t people just solve problems using rationality? Wouldn’t one domain-general rationality mechanism be more parsimonious than postulating many domain-specific mechanisms?

The issue of “rationality” is a complex one, to be addressed later
The modularity issue is also a matter of debate
Evolution theorists tend to favor the “swiss army knife” model

Note that Confer et al are discussing primarily behaviors related to sex and emotions
The area of intelligence and reasoning may be quite different

Aren’t human behaviors the result of learning and socialization, not evolution?

The false dichotomy: It's not learning versus evolution
Review the material on proximate vs. ultimate explanations
Consider language: Clearly we learn grammar and vocabulary
We could not do that without a built-in language module

How does evolutionary psychology take culture into account?

Cultural explanations are usually proximate explanations
These in turn have ultimate explanations
I.e., Why does a certain culture have a certain set of beliefs or attitudes?
Again, beware a false dichotomy
A recent theoretical development: Gene-culture coevolution

How do recent novel environmental phenomena affect human evolutionary psychology?

Many behaviors evolved as an adaptation to an environment that no longer exists
This can generate behavior that is maladaptive now
Evolution is a slow process, but may show effects surprisingly quickly
Example: Left handedness

What role do genes play in the framework of evolutionary psychology?

"Genetic determinism": A common concern, but a non-issue. Genes never uniquely determine behavior
The role of genes in evolutionary theories of behavior: Using Marr’s terminology, a difference between the algorithmic and the implementation levels

What is the practical value of evolutionary psychology?

In principle, if one understands the environmental pressures that induce a behavior, one is better situated to modify it
Possible examples: Treatment of depression, addressing violence and aggression

What contributions to cognitive science does evolutionary psychological offer?
Are there issues in cognitive science that can only be addressed adequately by taking an evolutionary approach?

Is an evolutionary perspective essential?
Can one develop a complete cognitive science without addressing the evolutionary issues?
Can proximate theories be considered separately from ultimate theories

Complex structures can emerge gradually
E.g., the eye – any light sensitivity is useful
Evolution is not a random process: The natural selection process is far from random
Evolution is very efficient.

Evolution is a rational decision maker:
What benefit does a feature offer? What is the cost? If cost exceeds benefit, get rid of it

Given enough time, and variability, evolution can solve any problem
Orgel’s rule: “Evolution is cleverer than you are” (Leslie Orgel, 1927-2007)
As we have seen, the “innate versus acquired” debate presumes a false dichotomy
Innate does not mean unchangeable. In fact, evolution may facilitate change (Capacity for change may evolve)

The existence of innate differences among people is not a justification for discrimination.
Beware the naturalistic fallacy - the assumption that because something is innate it is therefore good.
Beware using an explanation an excuse (“My genes made me do it”)
Neither genetic nor environmental factors are any more or less "under our control"

Class Notes: Evolutionary Approaches