These studies are all valid to a certain extent as they are all naturalistic experiments and therefore demand characteristic are not a factor in the findings. However, these studies are mostly correlational, as they do not state a link between cause and effect. Confounding variables also play a big part in these studies. These studies were mostly carried out in southern North America where the temperature is always hot and therefore only extremely warm temperatures would be seen as abnormal.
This evidence is both supported and challenged by Baron & Rosenberger who showed that the relationship between temperature and aggressive behaviour is a curvilinear one. This means that as temperature increases, so does aggressive behaviour. However, once the temperature reaches a certain high, then it becomes too warm to be aggressive as the body is concerning itself with keeping cool and effectively it is too warm to be aggressive. This is supported by the negative effect escape model which explains the curvilinear relationship between temperature and aggression.
Showing that once the temperature is at a certain point the individual become preoccupied with keeping cool that aggressive behaviour is not an option. The third perspective into aggressive behaviour and environmental factors is Noise. When noise is uncomfortably loud of at high pitch, people will become more aggressive than if there was no noise present. Geen & O’Neil (1969) found that high intensity noise increased aggression only in already aggressive people (who has just previously watched a violent film) Non-aggressive people did not become aggressive by the noise.
The key study into noise and aggression is by Donnerstein & Wilson (1976). They asked male participants to write a short essay which was then evaluated by a confederate, who marked them in a favourably (non-angered condition) or critically (angered condition). The participants were then asked to administer electric shocks to the confederates who had marked their essay. They were also exposed to bursts of high-density noise. Participants in the angered condition were much more likely to give more and longer shocks if they heard the noise than those who did not.
Participants in the non-angered condition were unaffected by the noise. This study provides some, but not many explanations into noise and aggression. It does not explain why people who were not already angered did not react in an aggressive manner to the noise. It appears to show that noise onl releases already stored anger in a person and does not create anger in itself. This research shows that there is a correlation but there is no link between cause and effect.