Download evolution and behavior ppt

LO #11: EXAMINE ONE
EVOLUTIONARY
EXPLANATION OF
BEHAVIOR
DARWIN’S THEORY OF NATURAL
SELECTION
Those members of a species
who have characteristics which
are better suited to the
environment will be more likely
to survive, breed and thus pass
on these traits.
GALAPAGOS ISLANDS
• Darwin observed that Finches on different islands
had different types of beaks that were each suited
to getting to the food available in their particular
habitat.
• He concluded that the process of natural selection
over several generations resulted in adaptation
which means the best beak was passed down until
it was the only beak.
INTERESTING FACT
Darwin did not know how
traits were passed down to
the offspring through
genes.
LINK FROM ANIMALS TO HUMANS
• In The Descent of Man (1871) Darwin noted that
humans have a number of behaviors in common
with other animals including mate selection, love of
mother for offspring, and self-preservation. Darwin,
thus, laid the foundation for psychologists to study
animals as a way of gaining insight into human
behavior.
IS THIS THE RESULT OF EVOLUTION IN
HUMANS?
SPATIAL MEMORY (MATSUZAWA, 2007)
• AIM: to study spatial memory in chimpanzees and
humans.
• PROCEDURES: Chimps were taught to recognize
numbers 1-9 on a computer monitor. Later, chimps
and humans were shown numbers flashed briefly on
a computer screen in random sequence. The
numbers were then replaced with blank squares,
and the participant had to remember which
number appeared in which location and touch the
square in the appropriate sequence.
FINDINGS
• Human participants made many errors while chimps
showed remarkable memory for the spatial
distribution of the numbers. Psychologists argue
that spatial memory in chimps has adapted over
time so that they can find scarce food resources.
Humans don’t need this skill to survive, so this
memory power might now be used by humans to
develop language memory.
DISGUST STUDY (FESSLER, 2006)
• AIM: To prove that pregnant women experience
nausea because it helps them avoid potentially
harmful food that their bodies could not fight off
with a suppressed immune system. (Fact: The
immune system in pregnant women is suppressed so
that the body won’t try to fight off the foreign
genetic material in her womb.)
METHOD
496 pregnant women were given a survey to
determine whether they were experiencing morning
sickness. They were then asked to consider 32
potentially stomach-turning scenarios (ex. maggots on
a piece of meat, a fish hook stuck through a finger)
and respond with levels of disgust.
FINDINGS
• Only the disgusting scenarios involving food earned
the highest ratings of disgust.
• Women who were in the first trimester of pregnancy
scored higher on the disgust scale.
• Fessler concluded that natural selection produced
the nausea response in pregnant women so they
would avoid foods that were a higher risk for
disease, especially during the first trimester when
they were most susceptible.
INTERNET DISGUST STUDY (CURTIS,
2004)
• AIM: To compare disgust responses to images of
infectious or potentially harmful things to images of
harmless things.
• METHOD: 77,000 male and female participants from
165 different countries were shown computer
images of harmful and harmless things. For each
image they were asked to rank their level of disgust.
FINDINGS
• The disgust reaction was the strongest for images
that threatened the immune system.
• Disgust reactions decreased with age.
• Women were more disgusted than men.
This supports the idea that
disgust is a key to successful
reproduction and thus survival of
the species.
LIMITATIONS OF EVOLUTIONARY
EVIDENCE
• Confirmation bias is possible where the
research see what they expect to see.
This is true because some theories are
difficult to test empirically.
• We don’t really know what the
behavior of early Homo Sapiens was.
• The evidence often underestimates
the role of cultural influences.
LO #12: DISCUSS ETHICAL
CONSIDERATIONS IN RESEARCH INTO
GENETIC INFLUENCES ON BEHAVIOR
• 1. Participants should be informed of
the aim, procedures, and any
potential harm (including
implications/predispositions for
unwanted condition) and give their
consent.
• This must be done in plain language
• Right to withdraw
ETHICAL CONSIDERATIONS (CONT.)
• 2. Confidentiality and privacy should
be protected. Participants must be
informed what will happen to any
genetic information obtained as part
of the study.
• Reason: Genetic info can be misused by
stigmatizing participants, affecting their
ability to get jobs, insurance. It can even
affect their legal rights.
ETHICAL CONSIDERATIONS (CONT.)
• Confidentiality can be protected
with coding information or
anonymizing the sample (this
means even researchers cannot
link results to individual people).
Unfortunately, this limits the
scientific results.
ETHICAL CONSIDERATIONS (CONT.)
• 3. Genetic research can reveal
unexpected information that may
harm participants. Some examples
are misattributed paternity, adoption,
carrier of a genetic disorder.
• Counseling should be available for former
participants.
ETHICAL CONSIDERATIONS (CONT.)
4. Religious and cultural issues
• Cultural objections (genetic research
incongruent with culture)
ETHICAL CONSIDERATIONS (CONT.)
5. Political misuse of research
-findings are used to
marginalize a group in society
(eg. eugenics)