PSYC 3100 Lecture Notes - Electromagnetic Spectrum, Richard Dawkins, Behavioural Genetics
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Chapter 1: Clearing the Way for an Evolutionary Psychology
- Evolutionary psychology is an approach to psychology that takes seriously the idea that
our own species is a product of evolution. It is both old and new— old because it started
with Charles Darwin himself, who applied evolutionary thinking to human behavior in
his 1872 book The Expression of the Emotions in Man and Animals, and new because,
until the last decade or so, the theory of evolution has had relatively little impact on the
field of psychology.
- John Tooby and Leda Cosmides ( 1992) that many psychologists hold to a general set of
beliefs called the standard social science model, or SSSM, that has a pervasive
influence on their research and theories. The SSSM is a useful place to begin sketching
the landscape explored in this book precisely because evolutionary psychology disagrees
with the SSSM in several important ways..
o The SSSM has a long history that reaches back to the enlightenment philosophers,
long before the founding of psychology. It rests on three interrelated assumptions.
Assumption 1: The Blank Slate; Tabula Rasa
The blank slate embodies the idea that the human mind has no
inborn tendencies or inclinations.
Assumption 2: The Irrelevance of Biology
An equally important supporting pillar of the SSSM is the
assumption that biological constraints on human behavior are
minor and unimportant. With experience playing the leading role,
biological influences fade to the vanishing point. According to the
SSSM, humans have few if any “ instincts” and only a few basic,
biological drives, such as hunger, thirst, and sex.
Assumption 3: General- Purpose Learning Mechanisms.
According to the SSSM, experience exerts its effects through the
process of learning.
A general- purpose mechanism is one that can handle many
different kinds of input information and that can generate many
different kinds of output.
According to the SSSM, one or a very few learning mechanisms
account for all of human behavior.
- Critique of the Standard Social Science Model
o Tooby and Leda Cosmides ( 1992) have detailed the problems with the SSSM, we
discuss five interrelated issues: development, the nature/ nurture dichotomy,
learning, the unity of science, and design.
The SSSM Misunderstands the Nature of Development
A truly blank slate could not respond to the environment, since it
has no rules for how to respond.
The SSSM Draws a False Dichotomy Between Nature and Nurture
It is a mistake to divide the causes of behavior between nature and
There are several genes that affect skin color by coding for the
production of pigments, notably melanin, that darken the skin.
These genes are active at some spontaneous level at birth. But their
subsequent level of activity, which determines how much melanin
is produced and deposited in the skin, depends critically on one
feature of the environment: the level of uvb radiation ( one
component of sunlight).
The pattern of response that the melanin genes encode, producing
more melanin when we experience high levels of uvb and
disassembling the melanin molecules when uvb levels drop. This is
the so- called norm of reaction for the melanin complex, the rule
that translates environmental variation into changes in the
organism. Traits like suntanning, where evolution has crafted a
particular norm of reaction, are called facultative traits
Nature and nurture work together in the development of every trait.
Environmental Effects Cannot Be Explained by General Laws of
o Learning mechanisms tend to be specialized for specific
kinds of problems.
The SSSM Drives a Wedge Between the Natural and Social Sciences
The wedge between the natural and social sciences can be
illustrated by the fact that psychologists and biologists for the most
part study behavior in isolation from each other, as indicated by the
way they approach differences between men and women. Both
psychologists and biologists agree that, on average, men desire to
mate more often and with a greater variety of partners than women
do. But they disagree about the causes of the sex difference.
the SSSM tend to attribute these differences to cultural influences,
whereas biologists have an evolutionary explanation
Exempting the behavior of organisms from the principles of
biology is like exempting the behavior of atoms from the principles
The SSSM Lacks an Overarching Theory of Design
Evolutionary psychology explains why people respond to their
environments in the ways they do.
Traditional psychology is most concerned with mechanism, while
evolutionary psychology focuses on function.
o Tinbergen’s Levels of Explanation
Niko Tinbergen ; His major division is between proximate and ultimate
causes. Proximate questions ( explanations) have to do with
mechanisms. They are “ plumbing- and- wiring” explanations, and
generally answer “ how?” questions: How does the system work?
Ultimate questions ( explanations) concern the evolution of the trait.
Generally, they answer the question “ why?”: Why does this system exist,
and why does it have the form it does?
a. Developmental. Genes, gene- environment interactions; age and
sex- related variation
b. Physiological. Neuronal, hormonal, biochemical, and
c. Historical. Evolutionary origins; precursors.
c. Selective. Adaptive value; what problems does the trait solve?
o Margaret Mead and the Myth of Infinite Malleability
Mead is world famous for her writings on the culture of Samoa, a chain of
islands in the Southwest Pacific. In her classic book, Coming of Age in
Samoa, Mead ( 1928/ 1973) drew a picture of a carefree society in which
there was no selfishness or jealousy, and people avoided competition.
Mead claimed that children were reared communally without attachment
to their parents and so roamed freely in a sort of paradise where everyone
shared in their upbringing.
The only problem with this picture is that it is totally at odds with the facts
of Samoan life. Derek Freeman was an anthropologist who studied
Samoan culture during many field trips, stretching over several decades.
He found that Samoans are far from the carefree people of Mead’s
writings ( Freeman, 1996). They are strict in raising their children in
Margaret Mead and many others like her tried to show that human
behavior is almost infinitely malleable— that human behavior is, for all
interesting purposes, learned.
o Human Nature as Revealed by the Universal People
Donald Brown ( 1991) argues that anthropologists have vastly
underestimated the similarities among cultures simply because they are as
invisible to us as the air we breathe. He has described what he calls the
universal people— whose behavior is typical of every single human
Chapter 1: clearing the way for an evolutionary psychology. Evolutionary psychology is an approach to psychology that takes seriously the idea that our own species is a product of evolution. John tooby and leda cosmides ( 1992) that many psychologists hold to a general set of beliefs called the standard social science model, or sssm, that has a pervasive influence on their research and theories. Assumption 1: the blank slate; tabula rasa. The blank slate embodies the idea that the human mind has no inborn tendencies or inclinations. An equally important supporting pillar of the sssm is the assumption that biological constraints on human behavior are minor and unimportant. With experience playing the leading role, biological influences fade to the vanishing point. Sssm, humans have few if any instincts and only a few basic, biological drives, such as hunger, thirst, and sex. According to the sssm, experience exerts its effects through the process of learning.