Examine one evolutionary explanation of
behavior.
“ Genetics is the key to the past. Every human
gene must have an ancestor….each gene is a
message from our forebears and together they
contain the whole story of human evolution”
( Steve Jones, 1994, British Geneticist)
“Our modern skulls house a Stone Age mind
“ (Cosmides & Tooby)
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Evolutionary psychology is a combination of
evolutionary biology and cognitive
psychology. It sees the mind as a set of
evolved mechanisms, or adaptations, that
have promoted survival and reproduction.
Evolutionary Psychologists claim that all
behavior is a result of these evolved
mechanisms. Thus every behavior that we see
today is the result of an evolved process.
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To understand evolutionary psychology it is
necessary to have a basic understanding
of genes, inheritance, and the principles of
natural selection.
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Evolutionary psychology is
inspired by the work of Charles
Darwin and applies his ideas of
natural selection to the mind.
Natural selection is the
nonrandom process by which
biological traits become more
or less common in a
population as a function of
differential reproduction of
their bearers. It is a key
mechanism of evolution.
A+ info on Darwin’s work
http://embryology.med.unsw.edu.au/pdf/Origin_of_Sp
ecies.pdf
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Darwin's theory argues that all living species,
including humans, arrived at their current biological
form through a historical process involving random
inheritable changes (genetic mutations)
Some changes are adaptive, that is, they increase
an individual's chances of surviving and
reproducing.
Changes of this kind are more likely to be passed on
to the next generation (natural selection), while
changes that hinder survival are lost.
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Examples of adaptations which would have
promoted survival and reproduction are
behaviors such as aggression which might be
understood as an adaptive necessity in the
competition for limited resources.
Food preferences for sweet tastes might be
understood as a adaptive urge to seek out
scarce sweet, ripe fruits which provided energy.
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Even mental disorders might be explained from an
evolutionary perspective.
Depression may be explained as an adaptive urge to
strategic ally withdrawal to conserve energy and
regroup after a setback of some kind.
Anorexia may have evolved from rationing
tendencies. During human evolution it would not
have been adaptive to always eat everything in site,
but rather it would have important to effectively
ration during lean times, as well as eating up during
more abundant times. Thus, the capacity to "go
without food" would have been important for survival.
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Attachment is a deep and enduring
emotional bond that connects one
person to another across time and
space (Ainsworth, 1973; Bowlby,
1969).
Attachment does not have to be
reciprocal. One person may have
an attachment with an individual
which is not shared.
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Attachment is characterized by
specific behaviors in children, such
as seeking proximity with the
attachment figure when upset or
threatened (Bowlby, 1969).
It appears to be a behavior that
ALL living creatures have encoded
in their genes.
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If the sole purpose of a gene is to ensure
survival, having parents that have the gene
that influences bonding would ensure the
survival of the offspring.
Having children with an innate push to form
attachments will also ensure the protection of
the child (along with the gene).
This is suggesting that attachments are
inherited from parents and expressed
regardless of the environment.
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Attachment theory in
psychology originates with
the seminal work of John
Bowlby (1958).
In the 1930’s John Bowlby
worked as a psychiatrist in
a Child Guidance Clinic in
London, where he treated
many emotionally
disturbed children.
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This experience led Bowlby to consider the
importance of the child’s relationship with
their mother in terms of their social, emotional
and cognitive development.
Specifically, it shaped his belief about the link
between early infant separations with the
mother and later maladjustment, and led
Bowlby to formulate his attachment theory.
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Adaptive Behavior – According to Bowlby,
infants have an innate desire to attach to their
mothers as it increases their chances of survival.
If a mother does not care for her child, the
child will die and therefore the mother’s genes
will also die.
Due to this process, mothers now have a gene
for looking after their babies.
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In 1935 Konrad Lorenz
supported the evolutionary
attachment thesis with young
ducklings and goslings.
He observed that at a certain
critical stage soon after
hatching, they learn to follow
real or foster parents.
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He divided goose eggs into two groups and marked
each goose once hatched so he knew which geese
were in which group.
One group was hatched with the mother goose and
one group was hatched with Lorenz.
The geese that were hatched with Lorenz followed
him and attached to him as if he were their mother
and showed distress if they lost sight of him, none
of the geese in this group became attached to their
real mother goose.
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The process, which is called imprinting,
involves visual and auditory stimuli from
the parent object; these elicit a following
response in the young that affects their
subsequent adult behavior.
http://www.youtube.com/watch?v=2UIU9X
H-mUI&feature=related
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Harlow did a number of studies on an avolutionary
theory of attachment in monkeys during the
1950's.
He stated that monkeys must form their
attachments during the first year of life (critical
period). His experiments took several forms:
 1. Infant monkeys reared in isolation – some died, others
were frightened and behaved in an abnormal manner.
They could not interact with other monkeys even when
they were older.
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Harlow did a number of studies on an evolutionary
theory of attachment in monkeys during the
1950's.
He stated that monkeys must form their
attachments during the first year of life (critical
period). His experiments took several forms:
http://youtu.be/hsA5Sec6dAI
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This supports the evolutionary theory of
attachment, in that the rhesus monkeys seem to
innately seek out meaningful attachments.
Harlow concluded that for a monkey to develop
normally s/he must have some interaction with an
object to which they can cling during the first
months of life (critical period).
Clinging, according to Bowlby and Harlow, is a
natural response - in times of stress the monkey
runs to the object to which it normally clings as if
the clinging decreases the stress.
Evaluate
each study:
◦Does the research exclude social and
cultural factors that could also influence
attachments?
◦Are their ethical concerns that we must
consider?
Multiple
research studies have supported a
perceived innate drive for animals and
humans to form attachments.
Cross-cultural
research has shown the
behavior to be present in nearly every culture
(which suggest an innate drive to attach)
Research
into evolutionary explanations are
ethically impossible to conduct in humans
(this limits the research to computer models
and animals)
The
effect of evolution on behavior cannot
be “proven” directly because we have little
information on the behavior of our early
ancestors
Questions?