Violence

Front 1

How do the cases of Phineas Gage and his Spanish counterpart differ, and what could that tell us about the biological basis of psychopathy?

Back 1

After a metal tamping iron destroyed most of Phineas Gage’s left prefrontal cortex, Gage acquired antisocial characteristics: he would gamble, be sexually promiscuous, and frequently changed jobs, among other reckless behaviors. He did not have a family or extensive social support. Conversely, after a Spanish man suffered similar brain damage by falling on a fence, he did not acquire these characteristics: he successfully kept his job, and was surrounded by his wife, children, and parents, who financially supported him. The fact that Gage acquired antisocial behaviors while the Spanish man did not suggests that social factors may be preventative against the development of criminal behavior. Even if there is a biological or anatomical predictor of criminal behavior, social factors also have an influence. Of course, these two cases are presented as suggestions, not as proofs; there were many differences between them.
This influence of social factors is also observed in the Raine et al (1994) study that revealed an interaction between biological risks and maternal rejection in violent behavior, such that the presence of both causes an in increase in percent likelihood of violence, but not with the presence of either in isolation.

Front 2

Three prenatal events that can influence a child’s rate of violence and antisocial personality disorder (APD)

Back 2

A woman’s alcohol consumption during pregnancy is related to antisocial personality disorder (APD) in the unborn child. Cesare Lombroso identified some physical traits that are associated with criminal behavior, and it turns out that at least a few of these traits are also found in children with Fetal Alcohol Syndrome (FAS) – for example, ears lower on the head than usual, perhaps because of chemically-induced failure of the ears to rise upward in the 3rd-4th month. Too much maternal alcohol consumption during pregnancy causes FAS, and children with FAS are more likely to develop APD (antisocial personality disorder). It’s not just FAS in its full-blown form either; there is a dose-response relationship in which small amounts of alcohol appear to have small but measurable effects.
Similarly, Brennan et al (1999) have observed a dose-response relationship between a mother’s nicotine intake and offspring’s rate of violent crime. The more cigarettes a mother smoked daily during pregnancy, the more likely their child would be arrested for violent crimes later in life. A mother’s nicotine intake did not correlate with rates of nonviolent crime, suggesting a specific link between prenatal nicotine exposure and future violence.
Research also suggests that prenatal exposure to poor or insufficient nutrition increases the likelihood of the unborn child to develop APD. In a study that looked at the effects of wartime famine in the Netherlands (the infamous “hunger winter”), it was found that being subjected to this famine within the first two trimesters of prenatal life was associated with the risk of developing APD.

Front 3

Discuss how measurements of resting heart rate and skin conductance can be used in in violence-focused research. What are some findings of these studies?

Back 3

Resting heart rate and skin conductance are both used as measurements of physiological arousal. One study measured the resting heart rate of 3-year-old children, and then assessed their propensity towards aggressive behaviors at age 11. What they found was that the children who had lower resting heart rate at age 3 were more likely to be classified as aggressive at age 11. This suggests that resting heart rate is a predictor of antisocial behavior.
Another research study used electrodermal fear conditioning to predict criminal behavior. In this paradigm, 3-year-old subjects were presented with auditory tone pairings as their skin conductance was measured. During conditioning, a neutral tone (CS) was paired with an unpleasant tone (US), which caused a conditioned fear response to the previously neutral tone. Skin conductance to the previously neutral tone was the conditioned response (CR), and served as a measure of physiological arousal. What these researchers found was that by the time these children were 23 years of age, those that had become criminals had exhibited lower levels – or an absence – of electrodermal fear conditioning at age 3. This suggests that measures of electrodermal fear conditioning can be used as a predictor of future criminal behavior.
In these two studies, resting heart rate and skin conductance were used as measures of physiological arousal. In both cases, it was observed that lower levels of physiological arousal in childhood predict future aggressive or criminal behavior in adolescence or adulthood.

Front 4

What could explain the possible finding that one-time murderers have lower prefrontal activation than controls (as measured in a PET study), but multiple-murderers show normal levels of prefrontal activity?

Back 4

In a brain imaging study, 41 murderers were compared to controls (matched by age, sex, schizophrenia, etc.). The study revealed that the murderers exhibited less prefrontal activation than controls. An explanation for this finding is that since the prefrontal cortex is heavily implicated in self-control and behavioral inhibition, a decrease in related activity may cause reckless and damaging behavior, such as murder. In other words, those who had committed murder might have done so because their neural areas that otherwise would have prevented this behavior were “broken”.
However, Dr. Raine also showed us a functional image of a man who had committed multiple murders over a 12-year period. This man’s brain looked nearly identical to those of the controls, with normal levels of prefrontal activation. One interpretation for this finding is that carefully constructing, carrying out, and concealing plans of that nature requires high levels of cognitive control, thus also requires a certain level of prefrontal activation.
There are always different interpretations for findings such as these, and there is plenty of variation in neural activity and explicit behaviors. The lesson here is that though we might be able to use neural signatures as potential predictors of behavior in order to prevent violent crime, brain images are not diagnostic in and of themselves.

Front 5

Research participants are faced with the following dilemma: An out-of-control train is heading down the tracks, and if it is not stopped it will kill 5 people. You can either do nothing, and as a result 5 people will die, or you can push a heavy man off of a footbridge, which will stop the train, and as a result only that one man will die. How will the neural response of psychopaths differ from controls during this task? How can this result be interpreted?

Back 5

-Making moral judgments like this one is very uncomfortable for most people, and this moral unease is correlated with an increase of activity in the amygdala, a brain region associated with emotion response. People who have higher ratings of psychopathy exhibit less amygdala activation during this moral dilemma task. In other words, amygdala response to moral unease is negatively correlated with levels of psychopathy. This result suggests that even if psychopaths “know” right from wrong, they do not “feel” right from wrong.
Additionally, anatomical studies of amygdala volume have found that psychopaths show an 18% volume reduction of amygdala volume relative to matched controls. This suggests that amygdala volume predicts later violence.
Both of these studies implicate the amygdala as a relevant neural structure in the development or characterization of psychopathic behaviors.

Front 6

Amygdala Response

Back 6

-a brain region associated with emotion response
-amygdala response to moral unease is negatively correlated with levels of psychopathy
-moral unease is correlated with an increase of activity in the amygdala

Front 7

Rational Capacity

Back 7

-a person’s capacity to know right from wrong, and to know that an act they committed was immoral and/or illegal.
-In the legal system, if a convicted criminal is thought to have rational capacity, then they are considered responsible for their actions.
-This notion of culpability is inextricably intertwined with biological and neurological studies of criminal behavior.

Front 8

What is meant by “rational capacity”, and how does it relate to cases like the one of acquired pedophilia? Why could “blaming the brain” result in a slippery slope in terms of criminal punishment?

Back 8

Rational capacity is a person’s capacity to know right from wrong, and to know that an act they committed was immoral and/or illegal. In the legal system, if a convicted criminal is thought to have rational capacity, then they are considered responsible for their actions. This notion of culpability is inextricably intertwined with biological and neurological studies of criminal behavior. In the case of acquired pedophilia, it was concluded that the onset of pedophilic behaviors was caused by the growth of a tumor in the man’s prefrontal cortex. Once this tumor was removed, those behaviors disappeared. The question then stands whether or not the man was responsible for the actions he committed as a “result” of the tumor. Did this man know what he was doing was wrong? Did he have any control over his actions?
Perhaps some might say that he is “less responsible” than someone would be if they committed the same actions in the absence of a tumor. But does this mean that as soon as we have a biological explanation for someone’s behavior, that person is no longer culpable? How about psychopaths with reduced amygdala volume? This is the potential slippery slope: at some point we may have biological or neurological explanations for every potential crime, and we don’t want this to render our justice system insignificant.
That being said, this is a very philosophical question, with plenty of room for argument and disagreement. Instead of taking this answer at its face value, you should think through these issues yourself and come up with your own answer!