Hormones and behaviour

Question 1

Define hormones

Answer 1

Chemicals that affect behaviour (secreted by the endocrine system)

Question 2

Explain the production of hormones

Answer 2

• Hormones are secreted by pituitary gland in the endocrine system and are release directly into the bloodstream.
• it take longer to produce changes in behaviour than neurotransmitters.
• only react with target cells (an appropriate receptor site for the hormone).

Question 3

Define oxytocin

Answer 3

• produced by the hypothalamus and secreted by the pituitary gland.
• involved in childbirth and initiation of maternal behaviour.
• believed to play a role in social bonding and trust between people.

Question 4

Study for oxytocin 1

Answer 4

Baumgartner et al. (2008) - oxytocin &role in trust

Question 5

Aim 1

Answer 5

to investigate the role of oxytocin in creating trust between participants during a social game called the “trust game”.

Question 6

Procedure 1

Answer 6

• 49 participants were placed in an fMRI scanner.
• they received either oxytocin or a placebo via a nasal spray.
• participants were then told to act as investors in several rounds of a trust game with different trustees.
• this game is built upon the dilemma of either trusting or not trusting. trusting is profitable but there is also a risk in trusting.
• they were also informed that they were to engage in a risk game, which is the same as the trust game in terms of financial risk but it is played against a computer instead of a human partner.
• the participants received feedback from the experimenters.
• the procedure was divided into a pre-feedback and post-feedback phase, and feedback was given in between the two.
• the feedback given indicated about 50% of their decisions (in both games) resulted in poor investment cuz their trust was broken.

Question 7

Results 1

Answer 7

• participants who had received a placebo were more likely to decrease their rate of trust after they had been briefed that their trust had been broken.
• participants who had received oxytocin continued to invest at similar rates.
• participants in the oxytocin group showed decreases in response in the amygdala and caudate nucleus.
• amygdala: emotional processing and fear learning. it has many oxytocin receptors.
• caudate nucleus: learning and memory; reward-related responses and learning to trust.

Question 8

Conclusion 1

Answer 8

• it seems oxytocin may facilitate the expression of trust even after trust has been violated by potentially lowering defence mechanisms associated with social risk.
• researchers could only observe these behavioural and neural results when participants played the trust game but not when they played the risk game against the computer.
• this finding suggests oxytocin’s effect on trust only comes into play in interactions with real people.

Question 9

Evaluation 1

Answer 9

• lab experiment: high scientific rigour.
• established cause-and-effect relationship.
• can be applied to study social phobia development and betrayal.
• cannot be generalised to a larger population (low in ecological validity).
• a reductionist approach to conclude oxytocin alone plays an important role in creating trust as there may be other factors contributed to this cause.
• ethics: injection of oxytocin may cause stress and betrayal.

Question 10

Study 2

Answer 10

Kosfeld et al (2005) - the role of oxytocin in increasing trust in humans.

Question 11

Aim 2

Answer 11

to investigate the role of oxytocin in increasing trust in humans.

Question 12

Procedure 2

Answer 12

• participants were 128 healthy male students, who were randomly allocated into either the oxytocin group or placebo group (thru nasal spray).
• the researchers designed a trust game with real monetary stakes.
• participants have paired anonymously and played the role of either an investor or a trustee.
  step 1: both investors and the trustee received an endowment of 12 monetary units.
  step 2: investors need to decide how much of that to send to the trustee.
  step 3: the trustee decides how much of the remaining money to send back to the investor.
• the game was played 4 times in the same role with a new partner.
• in the end, the total earned monetary units were exchanged for real money.

Question 13

Results 2

Answer 13

• level of trust was higher in the oxytocin group than the control group (max. trust level: 45% oxytocin group 21% control)

Question 14

Conclusion 2

Answer 14

• oxytocin reduces risk aversion in general.

- oxytocin increases people’s trust in other humans.

Question 15

Evaluation 2

Answer 15

• random allocation: individual differences are eliminated.
• lab experiment: high scientific rigour, establishes a cause-and-effect relationship.
• the sample size is relatively big:
• cannot be generalised to a greater population as the participants used in this study are all male students (gender and age are standardised).
• • a reductionist approach to conclude oxytocin alone plays an important role in creating trust as there may be other factors contributed to this cause.
• ethics: injection of oxytocin may cause stress and betrayal.