SL - Hormones and behaviour - oxytocin and trust

Question 1

De Dreu (2011)

Answer 1

Aim ->
To discover the effect of oxytocin in explaining in-group and out-group behaviours.

Method ->
He used the Implicit Association Test (IAT) that measures people’s unconscious biases towards different groups. He had his Dutch participants completing an IAT where they had photos of native Dutch men and immigrant Morrocan men, plus a collection of positive and negative words. The IAT measured how strongly participants associated positive and negative words to the two different groups of people. To investigate the role of oxytocin in this task, De Dreu had half the participants receive a nasal dose of an oxytocin spray, while the other half received the same spray but without oxytocin in it (placebo condition).

Results ->
Findings were that oxytocin significantly increased in-group favouritism (preference) as participants who’d received oxytocin associated Dutch men with positive words significantly more strongly than they did Moroccan men.

Conclusion ->
De Dreu concluded that oxytocin can lead to intergroup biases in terms of behaviour because it motivates in-group favouritism. Such behaviour can plausibly be presented as giving a survival advantage to a group, and so gives support for the idea that in-group favouritism is an evolved behaviour, mediated by the biological factor of oxytocin.

Evaluation ->

✔
✔

❌
❌

Question 2

Kosfeld (2005)

Answer 2

CBA

Aim ->
To see if oxytocin might promote prosocial approach behaviours - such as trust - in humans.

Method ->
Participants were given a nasal spray either containing oxytocin or a saline placebo. ppts then played some games where they were given 12 monetary units (MUs) per game. At the end of these games, all ppts’ MUs would be converted to real money. Ppts were either given the role of trustee or investor. Investors in the game could invest 0, 4, 8 or 12 MUs with the ‘trustee’. This investment would be tripled and then the trustee would have the option to transfer back some of these units. This game aimed to give ppts the options of either trusting the trustee to give back money or keeping the units for themselves (a difficult decision could be made as trusting the trustee could lead to either the greatest profit or lead to a loss of monetary units)

Results ->
Those who’d inhaled oxytocin twice as likely to commit all of their MUs to the trustee than those in the placebo condition. The oxytocin group’s median investment was significantly higher than that of the control group.

Conclusion ->
The hormone oxytocin promotes trust between people. It specifically affects trust in interpersonal relationships.

Evaluation ->

✔ High validity -> high control. Additionally, there was the possibility that oxytocin simply made ppts risk more. Because of this, the experiment was repeated, except a computer was involved which would back-transfer random proportions of the enlarged investment. If oxytocin leads to greater risk-taking then these results should match the first experiment’s. The results did not match the original experiment so we can be sure that oxytocin only increases trust.
✔ Supported by De Dreu (2011) who found that oxytocin boosted in-group preference. Both studies displayed that oxytocin boosts cooperation between people.

❌ Low mundane realism and ecological validity -> it was in an unnatural setting so we don’t know if people would behave similarly in a natural setting. In addition, allocating fake money to random people is not a usual task so using results from this unusual task is probably incorrect.
❌

Question 3

De Dreu (2010)

Answer 3

Aim ->
To investigate the effect of the hormone oxytocin on trust

Method ->
De Dreu had half the participants receive a nasal dose of an oxytocin spray, while the other half received the same spray but without oxytocin in it (placebo condition). He used variations of the Prisoner’s Dilemma thought experiment as a way to measure his participants’ attitudes towards in-group and out-group members (ppts had been assigned to groups on the basis of a “trivial criterion”, meaning that there was no real significance to the groups that they were part of).

Results ->
De Dreu’s results showed that participants who’d received oxytocin stated that they trusted in-group members significantly more than out-group members. The findings also showed that the more negative the consequences of the task might be for in-group members, the more likely oxytocin-receiving participants were to adopt non-cooperation strategies when an out-group member was involved.

Conclusion ->
De Dreu concluded that oxytocin promotes in-group love and defensive aggression towards out-groups. It does not increase out-group derogation when there is no threat to the in-group.

Evaluation ->

✔
✔

❌
❌