Sample IB Psychology Question

Explain using examples the functions of two hormones on human behavior.

Cortisol and Memory

A hormone produced by adrenal glands in response to stress and to restore homeostasis. The glands are part of a system called the endocrine system. Hormones are chemical messengers carried by glands. Chronic stress may result in prolonged cortisol secretion, which can damage the immune system and impair memory.

Newcalmer et al. (1999) - experiment on cortisol and memory
To investigate how levels of cortisol levels interfere with verbal declarative memory.
Procedure: A self-selected sample (through and advertisement) of 51 normal and healthy people ages 18~30 was used. Randomized, controlled and double-blinded. 3 conditions.

Condition 1: A high level of cortisol (160 mg tablet), was given. Same as cortisol released in a stressful event.
Artificial cortisol is to know the result and procedure.
Condition 2: Low level of cortisol (40 mg tablet) same as minor stressful event.
Condition 3: A placebo

Results: The high leveled group performed worse on verbal memory test than the low level group and placebo group. The low level group showed no memory decrease.
Evaluation: It was controlled and randomized so it was possible to establish a cause and effect relationship. They received informed consent. Negative effect of cortisol levels was reversible so no harm was done.

Oxytocin
Oxytocin is secreted by the hypothalamus into the brain and into the bloodstream via the pituatory gland. Linked to increase in trust. Evolutionary psychologists say trust was critical in forming relationships or staying away from bad ones. Learning to trust in vital for survival. One way it could work is by reducing four reactions via the amygdala as a consequence of betrayal.

Baumgartner et al (2008)
The role of oxytocin in trust in economic behavior.

Aim: To investigate the role of oxytocin after breaches of trust in the trust game.

Procedure: The participants played a trust game used by scientists to study social interaction.

Findings: Oxytocin rise boosts trust/ increases trustworthiness. Flaws in brains ability to respond to oxytocin might contribute to social disorders.

Procedure: "Investor," player 1 gets a sum of money and must decide whether to keep it or share it with a "trustee." (player 2). What is shared is tripled. Player 2 must decide if the sum should be shared (trust) or kept ( violation of trust). fMRI scans were carried out on all participants. They received oxytocin or placebo via a nasal spray. Participants play against different trustees and were given feedback when the trust was broken by the experimenter.

Results:
Participants in the placebo group showed less trust after feedback of betrayal. They invested less. Participants in the oxytocin groups continued to invest at similar rates after receiving feedback of breech of trust. The fMRI scan showed decreases in responses in the amygdala and caudate nucleus. Amygdala is a part of our brain that is involved in basic emotions and has many receptors for oxytocin. The caudate nucleus is involved in learning and memory and plays a role in reward related responses and trust.

Evaluation
Oxytocin could explain why people are able to restore and trust and forgiveness in long-term relationships. fMRI gave us and idea about a possible correlation but gave us nothing definite about cause and effect. Giving the oxytocin artificially may not reflect a true physiological process. Oxytocin is very complex and it is too simplistic to call it the: "trust hormone."