Sample answers
1. Which three neurotransmitters make up Fischer’s “love cocktail?” For each one, state its primary function.
Dopamine, noradrenaline, and serotonin. Dopamine is linked to motivation and the brain's reward system. Noradrenaline is responsible for activating the sympathetic nervous system - increasing heart rate and breathing. Serotonin is responsible for mood - but in this case, lower levels of serotonin appear to lead to obsessive behaviour.
2. What are the key differences between a hormone and a neurotransmitter?
A hormone is secreted by a gland whereas a neurotransmitter is released from the terminal buttons of a neuron. Hormones are released into the bloodstream, rather than in the brain, and they take longer to break down than neurotransmitters.
3. How are two ways that neurotransmitters are “cleaned up” from the synapse?
Neurotransmitters may be broken down by enzymes (e.g. acetylcholinesterase or MAO) or they make be reabsorbed by the terminal buttons - a process called "reuptake."
4. What is one disadvantage of using an fMRI in research?
There are actually several disadvantages. First, when looking at the role of neurotransmitters, we cannot directly measure neurotransmitters in the brain, but instead, observe where there is activity in the brain where receptor sites for those neurotransmitters are located. This is an indirect way to observe the role of neurotransmitters. In addition, the environment of the fMRI is not very natural - so ecological validity is a concern. Finally, there is the problem of artifacts. A participant’s anxiety could lead to changes in the brain which are detected by the fMRI. In addition, noise from the fMRI itself may lead to false positives. Bennet’s already classic “dead salmon study” is good evidence of this.
5. Which research method was used in Fischer’s study of the role of neurotransmitters in passionate love?
It was a quasi-experiment. Since people were either in a state of passionate love or not, they could not be randomly allocated to conditions.
6. What did Baumgarten find happened in the brains of participants who received higher levels of oxytocin through nasal spray?
The activation of the amygdala was suppressed.
7. What was Walum et al’s conclusion about vasopressin in humans? What are two limitations of the research?
They concluded that increased vasopressin leads to an increase in marital satisfaction. One limitation is the validity of the construct of “marital satisfaction.” Secondly, this is being linked to animal studies. It is difficult to say that this is the same outcome as Winslow’s study with prairie voles.
8. What did Ditzen et al (2009) measure in their experiment on oxytocin? Why was this a sensible dependent variable?
Ditzen et al measured the levels of cortisol in the participants’ saliva. This is sensible because oxytocin reduces activity in the amygdala, which is part of the stress response. During the stress response, higher levels of cortisol are secreted. If oxytocin has an effect, then when discussing problematic issues, the couple should not experience the same level of the stress response as couples who have not received oxytocin.
9. What do evolutionary psychologists argue are the characteristics most associated with a history of good health and a strong immune system?
10. What is meant by the statement that MHC is inherited “co-dominantly?”
It means that both alleles are inherited and have the potential of being expressed.
IB Docs (2) Team
The following worksheet is a review of the biological approach within the human relationships unit. 
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