Sunday, 9 September 2018

Mental Health and the Brain Model

Because of my long term interest in mental health matters I recently decided to do a FutureLearn course on Psychology and Mental Health and the reading material included a paper by Peter Kinderman entitled A Psychological Model of Mental Disorder. This made me think that I should be looking at my evolutionary model of human intelligence to see whether it might be able to model some mental health problems. The model already predicts some weaknesses in how the human mind works in areas such as confirmation bias - so could it suggest possible causes for mental illness.

The evolutionary model is based on the idea that at the neuron level our brain works in exactly the same way as any other mammal but we have developed a tool, which we call language, to bridge over some of the weaknesses due to the way the animal brain has evolved. Some of these inherent weaknesses could underlie some mental health problems because the genetically evolved mechanism  is being asked to do a lot of extra work.

The following can be considered draft discussion notes looking at some of the areas which my model suggests there issues which could adversely affect mental health.
  • ·        Problem with negatives: Eyes do not directly record things that aren’t there – and the basic pattern matching routine used by our animal brain does not directly record negatives. The “blind watchmaker” of evolution gets over this by ranking patterns. For instance the mouse does not need a rule with a negative such as “Don’t eat the cheese if the cat is watching” because it has a top priority rule “If cat then run away” so it runs away before it has considered whether to eat the cheese. Scaled up this weakness almost certainly lies behind human confirmation bias – and while confirmation bias is not considered to be mental illness (we all have it) when scaled up it could exaggerate the effects of some of the following weaknesses.
  • ·        Poor risk analysis: From the moment it is born an animal has to play safe or be eaten. One result is that evolution favours the rapid learning of generalizations based on single adverse events on a “safety first” basis. This is one of the reasons why humans have a very poor innate understanding of risk (especially in cases of very low rick but high cost such as dying in a plane accident).  In extreme cases exposure to adverse events (or even hearing about them second hand) could lead to phobias.
  • ·        Trial & Error Learning and Speed Learning: Animals which live in some kind of social relationship often learn to achieve specific goals by trial and error copying – for instance an infant being brought up  by its parents. Such learning requires many repetitions and is automatically self correcting. Humans (particularly young children) use language as a “speed learning” tool – and almost certainly are using the short-cut which animals use to rapidly remember adverse events. Speed learning is a vital part of human intelligence – but bypasses the checks inherent in trial and error learning. Mental health may be affected is information that was speed learnt as a child proves inadequate, or downright wrong, when faced with real world challenges later in life. Such problems would be considered a “nurture” activated cause of mental illness.
  • ·        Following the Leader: In groups of social animals there is a natural tendency to follow the leader of the pack – and when scaled up to modern human life this “leader” may be a highly charismatic media personality. I am wondering if the mechanism can be introverted and individuals see themselves as the leader – which could lead to combined with confirmation bias lead to paranoia or obsessive behavior – or in the other direction lead to depressive behavior.
The above points all relate to the way that information is stored in the brain’s neural network – but the way information is retrieved may be relevant to people seeing visions or hearing voices. The “driving engine” in the model uses a window into memory which “contains” the top active nodes (up to about 7) representing the concepts were are currently under consideration. As we think about something the window dynamically moves through the memory network – both horizontally (looking at concepts at a similar level) of digging deeper to find more detail. I suspect that you sense “seeing” something when an appropriate node is selected to appear in the conscious window and I suspect that some people can “dig” deeper than others.  OK only an idea at this stage – but probably worth following up.

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