PsychDigest

Aggressive people could have a "warrior gene"

Image by assbach via Flickr

People with the so-called “warrior gene” exhibit higher levels of behavioural aggression in response to provocation, according to new research. In the experiment, subjects penalized opponents by administering varying amounts of hot sauce.

In the study--the first to examine a behavioural measure of aggression in response to provocation--subjects were asked to cause physical pain to an opponent they believed had taken money from them by administering varying amounts of hot sauce.

Their experiment synthesized work in psychology and behavioural economics.

This post was taken from our psychology newsletter, PsychDigest. You can subscribe to PsychDigest for R1200 (US$120) for 12 issues, or R110 (US$11) per issue.

Monoamine oxidase A is an enzyme that breaks down important neurotransmitters in the brain, including dopamine, norepinephrine, and serotonin. The enzyme is regulated by monoamine oxidase A gene (MAOA). Humans have various forms of the gene, resulting in different levels of enzymatic activity. People with the low-activity form (MAOA-L) produce less of the enzyme, while the high-activity form (MAOA-H) produces more of the enzyme.

Several studies have found a correlation between the low-activity form of MAOA and aggression in observational and survey-based studies. Only about a third of people in Western populations have the low-activity form of MAOA. By comparison, low-activity MAOA has been reported to be much more frequent (approaching two-thirds of people) in some populations that had a history of warfare. This led to a controversy over MAOA being dubbed the “warrior gene.”

A total of 78 male students took part in the experiment over networked computers. Each subject (A) first performed a vocabulary task in which they earned money. They were then told that an anonymous partner (B), linked over the network, could choose to take some of their earnings away from them. The original subject (A) could then choose to punish the taker (B) by forcing them to eat unpleasantly hot (spicy) sauce—but they had to pay to do so, so administering punishment was costly.

In reality, the “partner” who took money away was a computer, which allowed the researchers to control responses. No one actually ingested hot sauce.

Their results demonstrate that low-activity MAOA subjects displayed slightly higher levels of aggression overall than high-activity MAOA subjects.There was strong evidence for a gene-by-environment interaction, such that MAOA is less associated with the occurrence of aggression in the low-provocation condition (when the amount of money taken was low), but significantly predicted aggression in a high-provocation situation (when the amount of money taken was high).

The results support previous research suggesting that MAOA influences aggressive behaviour, with potentially important implications for interpersonal aggression, violence, political decision-making, and crime. The finding of genetic influences on aggression and punishment behaviour also questions the recently proposed idea that humans are “altruistic” punishers, who willingly punish free-riders for the good of the group. These results support theories of cooperation that propose there are mixed strategies in the population. Some people may punish more than others, and there may be an underlying evolutionary logic for doing so.

Sources:

Brown University (2009, January 19). “Warrior gene” predicts aggressive behavior after provocation. Brown University Media Relations. Retrieved March 8, 2009, from http://news.brown.edu/pressreleases/2009/01/hotsauce

McDermott, R., Tingley, D., Cowden, J., Frazzetto, G., & Johnson, D.D.P. (2009, February 17). Monoamine oxidase A gene (MAOA) predicts behavioral aggression following provocation. PNAS, 106(7). 2118-2123. Retrieved March 11, 2009, from the journal website at http://www.pnas.org/content/106/7/2118.abstract?sid=2f476c23-b1bb-4332-a070-e1532501a154.

Technorati Tags: aggression,violence,behavior,dopamine,norepinephrine,serotonin,MAOA

Related articles by Zemanta

• 'Warrior Gene' Predicts Aggressive Behavior After Provocation (biosingularity.wordpress.com)
• Are You an Angry Drunk? It's In Your Genes! (geeksaresexy.net)
• Showing anger 'is good for career' (telegraph.co.uk)
• Chill Out: Anger Is Bad For the Heart (fitsugar.com)
• Anger could kill warns study on heart patients (telegraph.co.uk)

Low self-esteem does not lead to aggression

Early adolescents with high self-esteem are more likely to react aggressively when they feel ashamed than their peers with lower levels of self-esteem. In contrast to conventional wisdom that low self-esteem underlies aggression, the study suggests that young teens with low self-esteem do not feel the need to protect their punctured egos.

For the study, the scientists involved 163 children between the ages of 10 and 13. A few weeks before participating in the on-line experiments, the youngster filled out a questionnaire designed to assess their levels of self-esteem and narcissism. The researchers measured self-esteem by assessing the degree to which participants were satisfied with themselves and the way they led their lives. Sample statements included, “Some kids like the kind of person they are,” and “Some kids are not very happy with the way they do a lot of things.” They were asked if they were like that.

Narcissism included grandiose views of themselves, inflated feelings of superiority and entitlement, and exploitative interpersonal attitudes, assessed by questions such as, “Without me, our class would be much less fun,” “Kids like me deserve something extra,” and “I often succeed in getting admiration.”

For the experiment, the children were told they would be competing on an Internet reaction-time game called FastKid! against an opponent of the same sex and age. In reality, there was no opponent; the computer controlled all events. Those who were randomly selected for the “shame condition” were told that their opponent was one of the worst players in the supposed tournament, and they should easily win; when they lost, their last-place ranking was displayed on a web site they believed that everyone could see.

The children were told they could blast their opponent with a loud noise after winning a trial. The narcissistic kids were more aggressive than others, but only after they had been shamed. “Narcissists seem highly motivated to create and maintain a grandiose view of self,” the researchers wrote. “They tend to interpret social situations in terms of how they reflect on the self, and they engage in self-regulatory strategies to protect self-esteem when they need to. As shameful situations constitute a threat to grandiosity, narcissistic shame-induced aggression can likely be viewed as defensive effort to maintain self-worth.”

The researchers found no support for the traditional view that low self-esteem underlies aggression. In fact, they found that high self-esteem increased narcissistic shame-induced aggression. “It could be that narcissistic kids with high self-esteem are more vulnerable to shameful events than are kids with low self-esteem,” they speculate. “Or, they may differ in the way they deal with those events.”

______________________________

Sources:

Thomaes, S., Bushman, B.J., Stegge, H., & Olthof, T. (2008, November/December). Trumping shame by blasts of noise: Narcissism, self-esteem, shame,a nd aggression in young adolescents. Child Development, 79(6). 1792–1801. Retrieved February 5, 2009, from Wiley Interscience at http://www3.interscience.wiley.com/journal/-121521008/abstract. The full article can be accessed online for $29.95.

University of Michigan (2008, December 19). Shame on us: Shaming some kids makes them more aggressive. University of Michigan News Service. Retrieved February 5, 2009, from http://www.ns.umich.edu/htdocs/-releases/story.php?id=6901

Girls twice as likely as boys to remain victims of bullying

Girls targeted by bullies at primary school are two and a half times more likely to remain victims than boys.

The researchers interviewed 663 children aged 6 to 9 about their bullying experiences. They also examined the peer hierarchies amongst the children by asking them to nominate the three children they liked most in their class. A follow-up questionnaire was issued when the children were aged 10 to 11.

The researchers found girls being directly victimised by bullies (being beaten and suffering physical or verbal threats) at six years old were significantly more likely to still be a direct victim at age 10. The study also revealed that the nature of bullying changes as children grow older, from direct victimisation (physical bullying and threats) to relational victimisation (spreading of malicious gossip or the withdrawal of friendships leading to social exclusion).

The study also revealed interesting information about the affect of bullying on the 171 children who dropped out of the study because they had actually moved schools. Examination of the data collected for all the original participants in the study revealed that those who moved schools were actually 49% more likely to have been victims of relational bullying. These children had significantly fewer friends and were in more hierarchically-organised classes.

These findings indicate that even at an early age some victims of bullying remain victims over a long period of time. The development and implementation of intervention programmes that help victims to escape further victimization in primary school are called for. The researchers added that the findings suggested school professionals, health practitioners and parents should be aware of children showing signs of both physical and emotional health problems, as these appeared to be important risk factors for becoming and remaining a victim.

______________________________

Sources:

University of Warwick (2009, January 12). Girls twice as likely as boys to remain victims of bullying. Retrieved January 26. 2009, from http://www2.warwick.ac.uk/newsandevents/pressreleases/girls_twice_as/

Wolke, D., Woods, S., & Samara, M. (2008, December 2). Who escapes or remains a victim of bullying in primary school? British Journal of Developmental Psychology [Article available online before print]. Retrieved January 26, 2009, from IngentaConnect at http://www.ingentaconnect.com/content/bpsoc/bjdp/pre-prints/313150. The article is only available to subscribers.

Why do some children become chronic victims of bullying?

As soon as children are old enough to interact socially, some become entrenched in chronic and increasing patterns of victimization by their peers.

This article will feature in PsychDigest vol. 2, no. 8 (December 2008).
Subscribe to PsychDigest

How likely are you to be bullied?

How fair is this? A researcher found that high-school students who viewed themselves as attractive had a 35 per cent increased chance of being indirectly victimized. On the other hand, male students who think of themselves as good looking, had a 25 per cent decreased risk of being bullied.

Link: High-school girls who consider themselves attractive from medicineworld.org