The Relationship Between Dysfunction of the Prefrontal Cortex and Antisocial Behaviour
Antisocial behaviour is a broad term covering any behaviour that causes damage and conflicts with the interests of society. This therefore includes violence, inappropriate behaviour, lack of empathy and verbal abuse which has all be associated to dysfunction of the prefrontal cortex. The prefrontal cortex plays a major role in social cognition. This is an umbrella term used for the cognitive processes for social interaction, such as inhibitory control, correct behavioural responses, and theory of mind. When damage is caused to inhibitory control it leads to emotional instability.
Behaviour becomes childish, argumentative, becoming irritable quickly and finding difficulty to control mood changes (Hawkins & Trobst, 2000). Many studies have supported this idea, one in a particular, the case of Phineas Gage, foreman of a railway construction crew. An accident involving explosives sent the rod into his head and through his left frontal lobe. He survived, however his personality completely changed. From an efficient, lively character he turned into someone who was childish, impatient and irresponsible.
Damasio et al (1994, as described by Carlson (2010)) believed the reason for this was due to the rod destroying the ventromedial prefrontal cortex which when functioning normally, suppresses emotional responses to suit the situation. This inability to obtain emotional equilibrium could therefore lead to exaggerated emotional responses and difficulty inhibiting these responses (Hawkins & Trobst, 2000). Dysfunction of the prefrontal cortex has shown to cause damaged to social problem solving skills, such an inability to demonstrate awareness of when certain behaviour is socially inappropriate.
Individuals with frontal lobe damage can have difficulty recognising facial expression and may not be aware when someone is angered by their behaviour. They are therefore unable to realise when to change their behaviour to avoid conflict (Hawkins & Trobst, 2000). The ventromedial prefrontal cortex is shown to be activated during identification of facial expressions for emotions. Knowing this, it explains why people with damage specifically to the prefrontal cortex who show inappropriate behaviour also have impairments to their understanding of emotional expressions.
This interpersonal inappropriateness behaviour has been shown in alcoholics. Cognitive deficits have been suggested to be due to neurotoxic effects of alcohol on the prefrontal cortex causing it to function similarly to people with prefrontal damage. Alcoholics were shown to overestimate what the emotion really was, therefore mislabelling a sad face an angry one. This inability to distinguish between facial emotions could potentially escalate leading to interpersonal conflicts (Uekermann & Daum, 2008).
Deception and moral cognition has been found to be affected by the prefrontal cortex according to recent neuroimaging studies. In particular, the anterior prefrontal cortex and ventromedial prefrontal cortex are areas shown to influence antisocial behaviour and emotional judgement. (Karim, Schneider, Lotze, Veit, Sauseng, Braun & Birbaumer, 2010) These areas of the prefrontal cortex has been viewed as key to changes of executive functions and emotional adaptation from childhood into early adulthood and therefore being a critical part in development (Eslinger, Flaherty-Craig & Benton, 2004).
It has recently been shown that damage to the prefrontal cortex at an early age leads to moral reasoning and behaviour deficits, suggesting that our morals can be fixed from an early age (Moll, Zahn, Oliveira Souza, Krueger and Grafman, 2005). A case study of Marlowe (1992) also supports these findings. PL who suffered brain injury at the age of four to the right prefrontal cortex suffered from social-moral difficulties where even when taught to follow mediated rules, they were ineffective. This inability to follow societies rule soon led to criminal behaviour at adolescence.
Aggression is a major factor which is associated with antisocial behaviour. These cognitive defects caused by damage to the prefrontal cortex could potentially cause aggressive behaviour. The Vietnam head Injury Study which found looked at whether patients with ventromedial prefrontal lesions were more at risk to displaying violence or verbal threats in a confrontational situation. They found that they had a higher frequency of aggressive behaviour than the control group or patients with lesions in different areas of the brain showing that the prefrontal cortex must influence this aggression. Grafman, Schwab, Warden, Pridgen, Brown & Salaza, 1995) However, some patients with lesions in different parts of the brain showed an increased tendency towards violence therefore it is difficult to say the ventromedial is the only influence. The link between aggressive behaviour and lesions to the prefrontal cortex has been discovered in psychiatric patients. By measuring the behavioural performance of Intermittent Explosive Disorder patients , known for their impulsive aggressive characteristics, it was found that they couldn’t distinguish between “anger”, “disgust” or “surprised” in a simple facial recognition task.
Overall the findings of the IED patients were similar to the patients with prefrontal lesions which further extends the evidence that dysfunction of the prefrontal cortex can lead to antisocial behaviour. (Best, Williams & Coccaro, 2002)By analysing different causal areas of antisocial behaviour, the evidence shows that dysfunction of the prefrontal cortex is always involved therefore we can conclude that there is compelling evidence for a link between the two.
Different areas have been shown to be prominent in different parts cognition and behaviour with the ventromedial prefrontal cortex being particularly active during violence compared to the anterior prefrontal cortex being associated more with moral cognition. However what still needs to be further researched is how harmful damage is at an early age and whether there is a maximum age in which these effects are less damaging. References Bear, M. F. , Connors, B. W. & Paradiso, M. A. (2001). Neuroscience: Exploring The Brain (2nd Edition).