Transcript File - ISN Psychology

Session 21
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Presentations due for Fridays session
Needs to include a mind map/plan of a model
exam response
5% deduction for late submissions
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Evolution is the changing in the inherited traits of a
species over time.
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Based on the assumption that living organisms face
environmental challenges.
Organisms that adapt the best have a greater
chance of passing there genes to the next
generations.
Organisms with specific genetic traits that enhance
survival are said to be naturally selected.
They are more likely to survive and pass those
traits on.
Many of the traits that you have been passed down
to you to help you survive.
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A principle of evolutionary psychology is that as
genes mutate, those that are advantageous are
passed down through a process of natural
selection. This is derived from Charles Darwin's
theory of evolution.
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Evolutionary psychologists attempt to explain how
certain human behaviours show how humans have
developed over time. Certain behaviours can be
explained by examining their evolutionary origins
and their identifying their ability to enhance
survival.
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I am going to show you 14 images
For each picture I am going to ask you to write
down the first emotion you feel when you look at
the image
You may find some of these pictures unpleasant.
You have the right to withdraw at any time
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Model Answer Intro
In this essay the behaviour which will be examined
in terms of an evolutionary explanation of
behaviour is the study of emotions, in particular
disgust.
Disgust: Noun
A feeling of revulsion or profound disapproval
aroused by something unpleasant or offensive.
•Ekman (1972), found facial expression for disgust was identical in
different cultures across the globe.
•Facial expression also produced in blind individuals and is correctly
interpreted by individuals born deaf.
•This evidence indicates an innate biological basis for the expression
and recognition of disgust. The recognition of disgust is also
important among species as it has been found that when an individual
sees another person looking disgusted after tasting a particular food,
he or she automatically infers that the food is bad and should not be
eaten.
• This evidence suggests that disgust is experienced and recognized
almost universally and strongly implicates its evolutionary
significance.
Curtis (2004) has even claimed that disgust could have been one of
the first words uttered by humans.
"The word 'yuck' is similar in languages all over the world. It seems
to be a proto-word," says Curtis.
Aim:
To investigate whether the ‘morning sickness’ experienced by
pregnant women has an evolutionary basis.
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Investigated women's experiences of nausea during pregnancy
(resulting in morning sickness).
During the first trimester, hormones suppress the immune
system in order to accustom the body to the foreign genetic
material growing in the womb.
He hypothesised that the heightened sense of disgust
experienced by women during this time was the body's way of
compensating for the lacking immune system.
Procedure:
A sample of 496 healthy pregnant women aged between 18
and 50 years old was used.
The women were asked to consider 32 stomach churning
scenarios such as:
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Walking barefoot and stepping on an earthworm
Someone accidently sticking a fishhook through their
finger
Maggots on a piece of meat in a outdoor trashcan
Before asking the women to rank how disgusting they
found the scenarios (using a survey), Fessler posed a
series of questions, designed to determine whether they
were experiencing morning sickness.
Findings & Conclusions:
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Women in the first trimester of their pregnancy scored
much
higher on scores across the board on disgust sensitivity
than
their counterparts in the second and third trimester.
They found the scenarios involving food most disgusting.
As many of the most harmful diseases are food-borne,
Fessler concluded that a heightened sense of disgust was
advantageous to our ancestors and allowed them to
survive long enough to produce offspring, who passed on
the same sensitivities.
It would have helped compensate for the increase
susceptibility to disease during early pregnancy, which is
a risky period due to the suppressed immune system, by
increasing the urge to be picky abut food.
Evaluation
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This study supports the role of disgust in aiding
reproduction, and thus, as an evolutionary behaviour.
The data was collected through questionnaires. Self
reports may not be a great way of measuring disgust.
It would have been better to confront them with real
disgust-eliciting objects.
The effect was big (but not hugely significant when using
statistical significance).
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Fessler’s study supports that disgust may be an
evolutionary behaviour as it may assist
reproduction of offspring and protection against
disease, thus having a greater chance of surviving
or living a longer life, having children passing on
genes to their offspring.
Aim:
Aim
To carry out research on the Internet to test
whether there were patterns in people’s disgust
responses.
Aim:
Procedure:
Used an online survey in which participants were shown
20 images.
Participants were asked to rank their level of disgust.
Among the 20 images were seven pairs in which one was
infectious or potentially harmful to the immune system,
and the other was visually similar but non-infectious—
for example, one pair was a plate of bodily fluids and a
plate of blue viscous liquid.
There were 77 000 participants from 165 countries.
Curtis et al (2004) results
Curtis et al. (2004) Internet survey on disgust
responses
Disgust reaction was most strongly elicited for those images which
threaten one’s immune system.
◦ Natural selection may have helped human ancestors to be more
disgusted at things which threatened the immune system to
avoid things that could potentially lead to diseases.
Women had higher disgust reactions than men.
◦ As women are carriers for offspring, they have a stronger
disgust reaction so as not to threaten the lives of unborn
offspring.
The disgust reaction also decreased with age.
The decrease of disgust with age may be explained by the fact
that the older a member of a species, the less likely they are to
reproduce.
Curtis et al. (2004) Internet survey on disgust
responses
Evaluation
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Curtis used 77 000 participants from 165 countries. Large sample
size and cross cultural = generalisable
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Provides support for Fessler et al (2005) and vice versa
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Self report measures of disgust = subjective
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Curtis (2004) study supports the role of disgust in
aiding reproduction, and thus, as an evolutionary
behaviour.
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But we can override the disgust response.
People find family less disgusting than strangers.
And when it comes to sex, we compromise
between our instinctive avoidance of disease and
our urge to reproduce.
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Recent research has also suggested that sensitivity to
disgust is related to ethnocentrism (Navarrete & Fessler,
2006) as well as various politically conservative issues
including abortion, immigration, homosexual marriage
and stem-cell research, as well as prejudice toward
homosexuals.
Disgust sensitivity has also been found to be correlated
with other variables such as right-wing authoritarianism,
religious fundamentalism (Terrizzi & Ventis, 2006) and
religious obsessions (Olatunji, Tolin, Huppert & Lohr,
2005).
*Ethnocentrism is judging another culture solely by the
values and standards of one's own culture.
In spite of such evidence, there are some things to consider
when examining an evolutionary argument.
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The theories are speculative – its difficult to carry out
experiments to clearly prove the theories
• Since it may be difficult to test empirically some evolutionbased theories, researchers may be susceptible to
confirmation bias— that is, they see what they expect to see.
The researcher Hayes (2005) states that there is a tendency to
ignore findings that don’t fit in with the theory confirmation
bias
• Little is known about the behaviour of early Homo sapiens, so
statements about how humans used to be are hypothetical.
• Evolutionary arguments often underestimate the role of
culture/nurture/the present environmental influences in
shaping behavior.
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There is some evidence to support evolutionary
explanation of disgust
◦ Fessler (2006) showed that disgust may be an
evolutionary behaviour as it may assist reproduction of
offspring by compensating for a suppressed immune
system.
◦ Curtis et al. (2004) found that the disgust reaction may
help to prevent sicknesses.
 Research suggests that disgust aids the survival of
the human species and is therefore an evolutionary
behaviour.
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Also need to consider other factors such as the
environment
Want to take part in some online disgust research?
http://www.yourmorals.org/explore.php