IB Psych Revision: Biological

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The biological approach is all about finding biological correlates of behavior. A biological correlate is when some neurotransmitter, hormone, brain area, or gene is correlated with a behavior. So if extra testerone is associated with increased aggression, testesterone is considered the biological correlate of the aggression.

Principles

Behavior is biologically determined by physiological processes such as the nervous system neurotransmitters (e.g. serotonin) and the endocrine system (hormones e.g. adrenalin increases heart rate and fight or flight response)

"All that is psychological is first physiological" (Sperry)

Patterns of behavior can be inherited through genetics

Some patterns of behavior may be a result of natural selection

The study of animals can inform our understanding of human behavior

Psychologists use rats and monkeys for a lot of research but the results cannot always be generalized to humans

Research Methods

Lab Experiments
- Vontrolled studies that attempt to find cause and effect relationships between independent and dependent variables
Neuroimaging allow you to find brain regions (biological correlates) of behavior

PET
fMRI

Correlational studies allow you to test the role of genetics vs. environment on behavior

Twin studies - twins reared apart to test the effect of genetic vs. environment on their behavior

Any differences found between twins reared apart are considered environmental

Family studies

Lesion studies allow you to find biological correlates of behavior, we assume the missing behavior and damaged brain area are related

Phineas Gage's personality changed because of damage to his frontal lobe area
HM
Clive Wearing

Physiology and Behavior

Explain one study related to localization of function in the brain

Broca's area and Hippocampus taxi driver study

Broca's Area

Aim: Broca noticed some patients had problems with speech production and he wanted to find out if their impediment was related to the brain
Method: Dissected the brains of the patients to look for lesions
Results: He found that there was an overlapping damaged area in the left frontal lobe of the patients
Evaluation: MRI results of Broca's patients showed more damage than just Broca's area (Dronkers et al., 2007)
- Dronkers results suggests that the speech production difficulty of Broca's patients may be due to more extensive brain damage than just Broca's area
- Plaza et al., (2009) found that patients other brain areas took over the function of Broca's area if their Broca's area was damaged
Conclusion: Broca's area is localized for some aspects of speech production but Broca's aphasia can be a combination of various lesions to brain areas beyond Broca's area
Here is a video of Broca's patients demonstrating a lack of speech fluency

Hippocampus and Spatial Navigation (Maguire et al., 2000)

Aim: Does the hippocampus play a role in spatial navigation?
Method: The independent variable was the group of people and how much they had been navigating - they compared London taxi drivers to a control group
The dependent variable was the hippocampus size
Results: They found that taxi drivers have a larger posterior hippocampus than the control group
The size of the posterior hippocampus positively correlated with how long the taxi drivers had been working as taxi drivers
Conclusion: This suggests that the posterior hippocampus has the localized function of spatial navigation
The longer you spend taxi driving the more it affects the posterior size of the hippocampus
This suggests that practicing navigation (a form of cognition) affects hippocampus size (physiology)
You can also use this study for the syllabus point of an interaction of cognition and physiology

Using one or more examples, explain effects of neurotransmission on human behavior

Serotonin and risky behavior and Serotonin and sexuality

Serotonin and Risky Male Behavior in Monkeys (Higley et al., 1996)

Aim: Is serotonin related to taking risks?
Method: A field study where they followed male monkeys who were migrating to new social groups
Measured the serotonin by extracting cerebrospinal flluid by placing needles in their spines
The independent variable was dividing the monkeys into high, mid-high, mid-low and low serotonin groups
The dependent variables were how aggressive the monkeys were observed to be, number of scars they had and death
Results: 11/49 of the monkeys who died had low serotonin levels
Conclusion: Monkeys with low levels of serotonin are more likely to take risks like fighting with other monkeys
Evaluation: This field study has high ecological validity but lacks the control of lab experiments
- Sex difference - What about female monkeys?
- External validity - Do these results generalize to human males?

Serotonin and Risky Female Behavior in Monkeys (Westergaard et al., 1999)

Aim: Is serotonin related to taking risks for females?
Method: Observational study of captive monkeys
The independent variable was the species of monkey: rhesus monkeys or pigtailed macaques
Rhesus monkeys are known to be aggressive
Pigtailed macaques are known to be friendly
The dependent variable was the level of serotonin they measured in the cerebrospinal fluid like Higley et al., 1996
Another dependent variable was how aggressive the monkeys behaved and how many wounds they had
They placed each monkey in same sex groups to see how they behaved
Results: Rhesus monkeys were more aggressive and had more wounds
Rhesus monkeys had less serotoninthan pigtailed macaques
Conclusion: Serotonin inhibits risky behavior in females as well
Evaluation: This field study has high ecological validity but lacks the control of lab experiments
- External validity - Do these results generalize to human females?

Serotonin and Gambling Monkeys (Long et al., 2009)

Aim: Test if serotonin levels are related to gambling risks in a controlled environment
Method: They manipulated the amount of serotonin the monkeys could produce by forcing a certain type of diet
Tryptophan is the raw material required to produce serotonin and is found in certain foods
The independent variable was the tryptophan level of the diet which was high or low in tryptophan
High tryptophan meant more serotonin should be produced than the low tryptophan diet
The dependent variable was the choice the monkey made in the gambling task
In the gambling task the monkey could choose a safe option which would guarantee they would get a normal amount of juice
There was a riskier option where they could get a low or high amount of juice
Results: The low tryptophan group chose the risky option whereas the high tryptophan group chose the safe option
Conclusion: Levels of tryptophan as determined by diet can affect serotonin levels and risky behavior
Evaluation: Lab experiment had a high amount of control but a small sample size (only 3 monkeys) and low ecological validity
Do these results generalize to humans?

Using one or more examples, explain functions of two hormones in human behavior

Testosterone and Oxytocin

Discuss two effects of the environment on physiological processes

Sleep deprivation and metabolism (coming soon)
Mirror Neurons (coming soon)
Brain plasticity (coming soon)

Examine one interaction between cognition and physiology in terms of behaviour

Mediation and gamma waves and Mental workout

IB Psych Revision

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