Radke et al (2015)

Aim

Investigated the relationships between perceiving a social threat, testosterone and the amygdala

Method

· 54 healthy females. Half of the participants were given a small dose of testosterone and the other half were given a placebo (manipulate testosterone)

· While in an fMRI scanner participants were shown pictures of faces, one at a time, that were either angry or happy.

· For each face that appeared on the screen participants have to "avoid" or "approach the face. They are told by the researcher which of these actions they must follow.

· As they have to lie perfectly still in the fMRI they avoid/approach the face by moving a joystick with their hand. So if they are told to approach- the stick will make the face appear larger as though it is coming towards them. If they are told to avoid- the face will become smaller as though it is moving further away.

· The motivation factor was the following of the researcher's instructions (avoid or approach)

While in the scanner the activity of the participants amygdala and prefrontal cortices were measured

Results

· Group with testosterone had more activation in their amygdala when they were approaching angry faces (when they were told to do so) than when they approached happy faces.

There was not a significant difference in the activation of the prefrontal cortex across groups

Conclusions

· Higher levels of testosterone increase function of the amydala and activate fight response (confront social threat)

· Testosterone levels play an important function in increasing the activation of the amygdala which will result in more emotional and physical readiness to react aggressively.

· The role of testosterone may be to help prepare for that confrontation, as shown by the fact that in the testosterone condition there was a higher activation of the amygdala when moving towards the angry face

Suggests that men are more likely to approach social threat

Evaluation

· Ecological validity = to what extent does a face moving closer or further on a screen represent a social threat in reality?

o Narrow definition of what constitutes a social threat

o More research needed on variety of types and amygdala activation in order to generalise results

· Mundane reality = doesn't represent real threat -> doesn't transfer to real life setting

· With individuals with existing damage/low functioning of the prefrontal cortex= they may not be able to regulate emotions/decisions which could explain why studies have shown low prefrontal cortex activity and high levels of testosterone in prison populations.

· Behaviours like violence, aggression and crime are complex and that drawing broad conclusions that ignore specific factors leads to erroneous statements/conclusions

· While testosterone might influence aggression at times when we are socially threatened by increasing the activation of the amygdala when we are approaching a threat, that alone does not explain how this can lead to acting in a violent manner, like punching or shooting someone- unprovoked

As the prefrontal cortex helps to make judgements/decisions and is involved in rational thinking (considering long term consequences) this is important to consider in terms of aggression. If we have high levels of testosterone- perhaps we won't react aggressively when we are threatened because we will be able to regulate that emotional reaction and think through our decisions.

Research Method

Laboratory Experiment

Ethics