2. I.B. Learning Outcomes
B11- With reference to relevant research
studies, to what extent does genetic
inheritance influence behavior?
I can explain how much our genes impact our
behavior.
3. Behavioral Genetics
The study of how the both genetics and the
environment contribute to individual variations
in human behavior.
Genes do not cause behavior, they create a
predisposition towards it.
Depression
4. Definition of a Gene
Genes are the working subunits of
DNA. Each gene contains a particular
set of instructions, usually coding for a
particular protein or for a particular
function.
5. Inheritance
Each offspring inherits traits from their
parents.
46 Chromosomes – 23 from Mom, 23 from
Dad
~20,000-25,000 genes
6. Key ideas about Genetics
Genes that we inherit from our parents give
rise to physiological functions which
contribute to physical and behavioral
characteristics.
One Gene does not lead to a behavior, it can
be a building block towards that behavior.
8. Separated Twin Studies
Identical Genetic Make Up
Different Environments
Look for similarities and differences between
monozygotic twins
Nature & Nurture
Is It All In the Genes?
9. Minnesota Twin Study:
Bouchard et al. (1990)
Learning Outcome: B11
Aim: To determine the extent that genetics impact the
behavior.
Method:
Participants: Self-Selected MZ twins reared together
(MZT) and MZ twins that were reared apart (MZA)
Performed 50 hours of interviews, tests, and surveys on
participants.
10. Minnesota Twin Study:
Bouchard et al. (1990) Cont.
Findings:
Intelligence testing showed that 70% of intelligence is
attributed to genetic variation.
Conclusions:
Intelligence among other characteristics are to a large
extent due to genetics
Critical Thinking?
11. 5-HTT Gene
A gene that is responsible for creating
proteins that influence the reuptake of
serotonin
Long-Allele (57% of population)
Short-Allele (43% of population)
12. Caspi et al. (2003)
Learning Outcome: B11
Aim: To determine whether the 5-HTT gene
predicts depression
Method:
Followed a group of adolescents for several years
and measured for stressful events.
When they were 26, they tested them for depression.
13. Caspi et al. (2003)
Findings:
Individuals who had a two short 5-HTT alleles
were more likely to be depressed following
stressful events.
Conclusion:
Genetics can predict the likelihood of
depression in individuals.
Critical Thinking?
14. Levenson (2013)
Aim: To determine the role of the 5-HTT gene in marital
satisfaction
Method: Followed couples since 1989 and surveyed
them on marital satisfaction.
Finding: Individuals with a short 5-HTT allele were
more likely to be unhappy in an unhealthy relationship
or happy in a healthy relationship.
Conclusion: Short Allele = More influenced by
environment.
Critical Thinking?
15. COMT Gene
COMT Gene: A gene that codes for an
enzyme that clears dopamine from the frontal
lobe.
This can impact how you deal with stress.
16. Warrior or Worrier?
Worrier:
Slow Acting Enzyme
No Stress: Higher
cognitive functioning,
attention, and
problem solving.
Stress: Meltdown
Warrior:
Fast Acting Enzyme
No Stress: Underwhelmed
by daily life and a lack of
problem solving &
concentration.
Stress: Concentration &
Problem Solving Sky
Rocket.
17. Chang et al (2009)
Aim: To investigate the role of the COMT Gene in
test performance.
Method:
Took blood samples from thousands of Taiwanese
students about to take their Basic Competency Test.
Performed a genetic test on each student.
Compared the scores for variants of COMT Gene.
18. Chang et al (2009)
Finding: Students with fast acting enzymes
(warriors) performed better than students with
slow acting enzymes (worriers).
Conclusions: The COMT gene impacted the
way that students performed under a stressful
situation.
Critical Thinking?
19. Parasuraman et al (2013)
Aim: To investigate the COMT Gene’s impact on
high stress multitasking.
Method:
99 participants were measured on their ability to
control six drones in an airforce simulation.
Findings:
Participants with the slow action enzyme (Worriers)
destroyed more targets than participants with fast
acting enzymes (warriors).
Conclusion: People with slow acting enzyme
variants were more effective at multitasking
complex tasks,
Critical Thinking?
20. Ethics of Genetic Research
Anonymity and Confidentiality.
Right to know who owns their genetic material and
with whom it will be shared.
Informed Consent
Genetic research could potentially be a risk to the
participants if misused.
Genetic Research can reveal information that is
unexpected or a source of distress (Learning that
you are predisposed to depression can lead to
depression)
21. Discussion Questions
Should the military, colleges, police forces, etc.
use genetic testing to help judge applicants?
Is it ethical to use genetics in determining who can
become a drone pilot or another job?
Do you want a genetic test? Why or why not?
To what extent do our genes impact our behavior?
