Oct 16 2009

Are Psychopaths Fearless?

One of my favorite current series is Dexter – a show that dares to have a psychopathic serial killer as a protagonist. Dexter regularly feeds his “dark passenger” by ritually killing people, but he lives by a code drilled into him by his adoptive police officer father – only kill people who deserve it. So the audience gets to watch brutal ritual murders, but the horror is tempered by our sense of justice and need for revenge.

What I find even more interesting is the running voice over – hearing Dexter’s thoughts as he goes through his day, trying to fit in with the world of “normal” people. Dexter has no clue about typical human emotions or behavior, and so in a way he provides an outsider’s view of humanity.

Although Dexter retains enough of a shadow of humanity to be likable as a protagonist, the writers have given him the typical personality profile of a psychopath, including being relatively fearless. Recently, however, psychologist Joseph Newman has questioned whether psychopaths are truly fearless, or perhaps they have some other deficit that explains their apparently fearlessness.

Newman did an interesting experiment, using a number of convicted criminals who fit the psychopathic personality type and normal controls. He made them perform a task where they would push a button to indicate if words appearing on a screen were red or green. Simultaneously they would occasionally get a shock after the red words, but never the green. Newman used strong blinking as a marker for anticipating the shock, and found that the psychopathic subjects flinched just as much as the controls.

He then repeated the experiment but had the subjects press a button to indicate if the words were in capitals or lower case. This time the controls flinched just as much when they saw the red words, but the psychopathic subjects did not. Taken at face value, this outcome could indicate that psychopathic subjects display just as much fear as controls, but that they are more easily distractable from that fear.

Of course, we cannot make firm conclusions from any one such psychological experiment. It is important to remember that when examining cortical function, whether as part of a neurological exam of a patient or a psychological experiment, we cannot peer into the brain and see directly what the different parts are doing. Rather, we look at tasks and then infer from those tasks which brain functions are working and which ones are impaired.

No task perfectly isolates one definable brain function, and so even for the most straightforward assessments we have to give patients or subjects various tasks to perform and then triangulate to the common element that is malfunctioning.

This also highlights the complexity of neuroscience research. We are still figuring out what all the different brain “modules” are – identifiable parts or networks within the brain that subsume a definable function. Some classic modules would include the primary language cortex, which can be further broken down into Wernicke’s area which translates words into ideas and ideas into words, and Broca’s area, which provides the exquisite motor control necessary to speak. There are also brain areas for visual processing, calculations, spacial processing, learned motor tasks, recognizing faces, and many other localized functions. These are the “classic” cortical functions, the ones a neurologist would use to localize a stroke, for example.

But neuroscience has been advancing tremendously in recent years, especially with the development of functional MRI imaging and transcranial magnetic stimulation. Neuroscientists are finding brain areas that have more abstract functions, like giving us a sense of ownership over our limbs, imparting emotional context to recognized objects, or making us feel as if we are inside our bodies.

One thing is for sure – the brain is damn complex. Human behavior results from many specific tendencies and abilities working together to create a final outcome. Researchers mainly look at those final outcomes, and then have to backtrack to all the various processes that contributed to them. Each individual person is a unique assortment of neurological abilities and tendencies out of the countless permutations that might exist.

For this reason researchers have to look at many individuals for statistical tendencies. And then they have to consider all the possible contributors within a complex interaction of many brain functions.

Newman’s research is just one example – apparent fearlessness may partly be due to being easily distracted. We’ll see – such questions have to be researched from many angles (triangulating) before we can be confident in any one interpretation.

Neuroscience researchers don’t have access to a Dexter-like running monologue of what people are really thinking – and what people are consciously thinking represents only a small part of total brain processing in any case. But slowly, researchers are grinding forward our understanding of brain function. The human brain is perhaps the most complex and fascinating subject of scientific study – in fact it is the process of the human brain trying to understand itself.

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