Friday, March 18, 2011

Psychopathy is a Selfish Behavioral Strategy that may be Programmed by Ecological Adversity

Psychopathy, sometimes known as antisocial personality disorder, is characterized by a lack of empathy and severely amoral conduct. Because people with psychopathy have so much trouble empathizing they are much less afraid to cross social boundaries, insult or hurt others. Because about 1% of the population are psychopaths evolutionary psychologists have come to believe that psychopathy may represent a viable ecological strategy that helps an individual to selfishly gain resources by taking advantage of others. Our hunting and gathering ancestors have relied on cooperation for millions of years and this is why most people are not psychopathic. Perhaps though, in small numbers, genes that influenced individuals to be less helpful and more selfish benefitted those that bore them explaining why psychopathy is heritable and why genes for psychopathy exist in the human genome. It is too bad that these genes can’t tell if the environment is a healthy, friendly one that is conducive to team playing or if it is a bad one which would reward those that defect from the team. Maybe the genes can tell...

A good deal of very interesting research points to the fact that environmental cues can switch on genes that would normally stay dormant, resulting in changes to the body and brain. For instance, water bugs whose mothers are stressed out by the scent of their natural predators make babies that have totally different protective armor. A huge number of similar “predictive adaptive responses” to environmental adversity have been documented in animals and even humans – many arising from prenatal stress. Studies of the Dutch Hunger Winter of 1944-1945 have shown that individuals born just after this famine are more likely to have lower metabolisms. This is thought to represent a predictive response to low food availability. Interestingly, these studies also show that these famine-born individuals are more likely to be psychopathic.
It is difficult to say exactly what this means, but it suggests to me that humans may be programmed by early environmental stress (and perhaps postnatal adversity too) to be selfish, manipulative, guiltless and antisocial. It would make sense for natural selection to program us to be more deceitful and cunning in a hostile environment that is marked by scarcity and thus high levels of competition. Such a change would force the person or animal to look out for number 1 – to look out for its genes. Peruse the following clinical rating scale from the PCL-R and ask yourself: “what kind of environment would these traits go along well with?”

Psychopathic Traits:

Factor 1: Aggressive narcissism
  1. Glibness/superficial charm
  2. Grandiose sense of self-worth
  3. Pathological lying
  4. Cunning/manipulative
  5. Lack of remorse or guilt
  6. Emotionally shallow
  7. Callous/lack of empathy
  8. Failure to accept responsibility for own actions

Factor 2: Socially deviant lifestyle
  1. Need for stimulation/proneness to boredom
  2. Parasitic lifestyle
  3. Poor behavioral control
  4. Promiscuous sexual behavior
  5. Lack of realistic, long-term goals
  6. Impulsiveness
  7. Irresponsibility
  8. Juvenile delinquency
  9. Early behavioral problems
  10. Revocation of conditional release

Here are some of my favorite books that explain how common human traits are actually adaptive biological responses:

Tuesday, March 15, 2011

Mapping the Spatial Relationships Between Cortical Inputs

The cerebral cortex is a big sheet of neurons about 2 millimeters thick with a surface area of about four 8.5 x 11 pages of paper. Under this thin sheet of gray matter (neuron bodies) lies all of the white matter that creates the connections between neurons. The physical characteristics of neurons differ a little throughout the sheet but the main differences - that determine what the neurons process – are found in the inputs. Inputs from the sense organs and other brain areas feed into the cortex in a distributed way. I believe, that if you want to know, in general, what a small patch of cortex does, the best way to do this is to look at the inputs that feed into it. Particular areas of cortex are programmed by not only the nearest input, but other nearby inputs. These inputs probably work together, triangulate or overlap like circles in a Venn diagram, to determine the relevant functional properties of nearby cortical tissue.
 Input from the retina feeds right into cortex in the back of the brain and this is why occipital cortical areas there process visual stimuli. Up near the top of the head, in the somatosensory strip, are inputs from sensors on the skin. This strip of cortex is thus responsible for processing touch information from all over the body. But what about half-way in between these two areas? What is processed in the space between visual and tactile? The parietal cortex sits in between these two areas and its main function seems to be almost a split between visual and somatosensory processing. The parietal cortex is responsible for our mental representations of personal space, the areas right around our body. Could it be that the function of parietal cortex is determined by a combination of its nearest inputs? I think so. As another example, consider the temporal lobe which receives inputs directly from the cochlea of the ear. As you might guess much of the temporal lobe is involved in identifying the source of heard sounds. Guess what the area intermediate between visual and auditory cortex is involved in? It is involved in the recognition of conceptual objects, normally things that both have visual forms and make audible sounds.
 In more complex areas you have several inputs, very close to each other, coming from sensory organs, other cortical areas and also neuromodulatory systems that release transmitters like dopamine, serotonin and adrenaline. This gets very complicated, very quickly, but I have a strong hunch that the unique connectional trigonometry of patches of cortex determines what kinds of things their neurons are exposed to and how they "perceive" the world. Many diagrams that I have seen in neuroscience display the inputs and outputs associated with different areas but contain no information about the spatial orientation of these inputs relative to each other. For many reasons, I think that the spatial configuration of cortical inputs is very important and will be instrumental in determining function in different cortical areas - especially those with multiple, multimodal, overlapping inputs such as the prefrontal cortex.