Transcript Ch_08x

CHAPTER EIGHT
The Evolutionary Approach: Change Over Time
Natural Selection
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EP relies on Darwin’s (1859) theory of natural
selection. It requires three elements:
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Variation in traits within a species.
The passing of genetic material from one generation to
the next, called inheritance.
Selection, which is a change in the environment that
favors one trait over another.
Evolved Psychological Mechanisms
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EP views the mind as a collection of special purpose
devices or a “Swiss army knife.”
Each device evolved under selection pressures to
solve a specific problem.
These mechanisms can be considered as modules.
This is in contrast to the traditional notion of mind as
a general purpose processor.
Comparative Cognition
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The cross-species study of cognitive ability.
Each species is adapted to its ecological niche.
Animal Memory
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Object permanence is the ability to know that an
object still exists even though it cannot be
perceived.
Dogs have this capacity. They will look for a toy
that has been hidden behind boxes (Gagnon &
Dore, 1994).
It requires memory and is adaptive for locating
prey that have disappeared behind obstacles.
Animal Memory
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Memory is also useful for remembering where you
have already searched so you don’t have to look in
the same place twice.
The Hawaiian honeycreeper bird can remember
which flowers it has already fed from.
The nutcracker bird can store up to 33,000 pine
nuts in 6,000 different sites in the summer and
remember them when it comes back in the winter
and spring!
Animal Problem Solving
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Kohler’s chimps and insight learning
Transitive inference is like deductive reasoning. It
involves knowing that if A is bigger than B and B is
bigger than C, then A is bigger than C.
Squirrel monkeys can deduce which colored box
contains a peanut (McGonigle & Chalmers, 1977).
Pigeons and rats can also solve transitive inference
problems (Davis, 1992).
Comparative Neuroscience
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Involves comparing the brains of different animal
species.
Do smarter animals have bigger brains?
We must adjust for body size. The cephalization
index does this.
But factors other than intelligence influence brain
size. Birds have small brains because they need to
be light to fly. Dolphins have larger brains because
water can support a large body weight.
The Cephalization Index
Comparative Neuroscience
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Also, not every part of a brain “does” cognition.
The hindbrain mostly regulates basic physiological
function.
The cortex, especially the neocortex is the part most
closely linked to cognition.
The neocortex is 80% of total brain volume for
humans. In primates it is 50% and in rodents it is
30%.
Evolutionary Psychology
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Evolutionary Psychology (EP) describes how our early
environment produced our current mental abilities.
This environment was the the Pleistocene era,
approximately two million years ago, referred to as
the Environment of Evolutionary Adaptation (EEA).
Evidence to support evolutionary hypotheses comes
from archeological records, hunter-gatherer societies,
between- and within-species comparisons, and
experimentation.
Evolutionary Psychology
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The traditional view in cognitive psychology is that
brains are general purpose processor. They can solve
any problem of a given type.
The evolutionary view is that specific cognitive
abilities have developed to solve specific adaptive
problems. These abilities are referred to as evolved
psychological mechanisms.
Cosmides and Tooby (19920 refer to the evolutionary
brain as a “Swiss Army Knife”.
Evolution and Categorization
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We form concepts in a graded, continuous fashion, not
“all or none.”
Natural categories are also continuous. The mind
mimics this organization.
This allows us to generalize our knowledge from one
category to another.
Concepts are organized around representative
members of a class, the typicality effect.
Which Looks More Like a Bird?
Evolution and Memory
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We should have a better memory for information
we are exposed to more often.
This is because it is more relevant to our survival.
Recall for words is proportional to their frequency
of occurrence (Anderson and Schooler, 1991).
The Wason Selection Task – Hard Version
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You have been hired as a clerk. Your job is to make sure that a set of
documents is marked correctly, according to the following rule: "If the
document has an E rating, then it must be marked code 4." You have
been told that there are some errors in the coding of the documents,
and that you need to find the errors. Each document has a letter rating
on one side and a numerical code on the other. Here are four
documents. Which document(s) do you need to turn over to check for
errors?
The Wason Selection Task – Easy Version
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You have been hired as a bouncer in a bar and you must enforce
the following rule: "If a person is drinking vodka, then he must be
over twenty years old." The cards above have information about
four people in the bar. One side of each card lists a person's age
and the other side shows what he or she is drinking. Which card(s)
do you need to turn over to be sure no one is breaking the law?
Evolution and Logical Reasoning
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The bouncer problem is easy because it involves
cheater-detection.
In the EEA it was important to detect who might be
cheating because in small groups with limited
resources it might mean less for you (Cosmides and
Tooby, 1992).
The logic module thus works only in this context,
implying logic is not domain general.
Evolution and Judgment Under
Uncertainty
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Uncertain judgments occur when we make a
decision without complete information.
Most everyday decisions in life are like this.
In such cases, we often rely on heuristics.
But heuristics can lead us to commit fallacies, a
misunderstanding of statistical rules.
Fallacies
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Base-rate fallacy. Ignoring base rates. Example:
Jack the lawyer/engineer.
Conjunction fallacy. Ignoring the conjunction rule.
Example: Linda the bank teller.
Gambler’s fallacy. Ignoring independent outcomes.
Example: gambling.
Evolution and Language
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Language may have evolved to promote social
bonding (Dunbar, 1996).
It allows for complex coordinated social behavior.
Examples: improvements in hunting, foraging, and
childcare.
It may also play a role in sexual selection.
Evolution and Sex Differences
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Attributed to a sexual division of labor in which men
hunted and women gathered.
Hunting may have fostered increased spatial ability
in men.
Gathering may have promoted increased verbal
abilities in women.
But above distinction is too broad. Women are
better at object location memory.
Behavioral Economics
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The study of economic decision making and the
factors that affect it.
Classical view is that people are rational and
always make choices that increase their money or
value.
In reality the way we think about money is affected
by heuristics and evolution, just as we discussed in
the prior section.
The Ultimatum Game
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How would you split a $1,000 with someone else?
Your partner would refuse to accept up until a split
of about 70-30 (Camerer, 2003).
Why turn down free cash?
Because the split is perceived as unfair. In small
societies reciprocal altruism is the rule. Favors are
expected to be returned. If you cheat someone now,
they will probably cheat you later.
Loss Aversion
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You are on a team of experts that must decide what
course of action to take in preventing a flu outbreak.
Program A. 200 people will be saved.
Program B. There is a one-third probability that 600
people will be saved, and a two-thirds probability
that no people will be saved.
A full 72% of the participants in one experiment
chose option A.
Loss Aversion
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Now consider the following re-wording of the
question:
Program C. 400 people will die.
Program D. There is a one-third probability that
nobody will die, and a two-thirds probability that
600 people will die.
The outcomes in this second case are identical to that
in the first, yet now the responses are reversed.
Seventy eight percent now chose program D over
program C.
Framing Effects
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Option A. TheMePhone is available at Awesome
Electronics for $100; five blocks away at DigiData it
is at half price for only $50. Would you make the
short trip to save the $50?
Option B. PowerPurchase offers the NetBook for
$1,000; five blocks away it can be had for $950 at
CircuitCrazy. Would you make the short trip to save
the $50?
The majority of people when presented with this
problem prefer option A.
Mental Accounting
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We put money into different categories depending
on the amount. We reason differently about smaller
sums than we do larger ones.
$50 seems like more money when compared to
$100 than to $1,000.
The Endowment Effect
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One group is given a choice of investments. They
chose based on how risk averse they are.
In a second condition the same group is already
given an investment.
They are more likely to stick with what they were
given. 47% stayed with it, compared to 32% of
those who had chosen it earlier.
The Sunk-Cost Fallacy
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We tend to stick with those things we’ve already put
a lot of time, energy, or money into.
Example: Chris prefers his “old clunker” car because
he just spent a $1,000 to fix it.
This can be irrational, since the old car is more likely
to break down and cost more money in the future
compared to a better car.
Evaluating the Evolutionary Approach
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Novel biological function need not arise to service
survival or reproduction. Other mechanisms:
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Exaptation or neutral drift. Random mutation.
Molecular drive. Copies of genes mutate.
Idea of a spandrel (Gould, 2000). Byproducts of
adaptations.
Spandrels in Architecture
Interdisciplinary Crossroads: Artificial
Life
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The study of manmade systems that behave in ways
characteristic of natural living systems (Langton,
1989).
Computer “creatures” are created through
evolutionary rules. They navigate, seek out prey, and
avoid predators in a virtual environment.
Complex adaptive behaviors emerge including
parasitism, symbiosis, and flocking.