Number
13
I am really Excited.
I can't wait to tell you about it.
See Later Follow Up Discussion Papers
I am currently preparing a talk How Evolution has made us the way we are – and I
had a problem. You can't really assess how evolution has affected the development of the human mind unless you have a clear model of how the brain processes and
stores information. I have already, in earlier brain storms on this
blog pointed to the black hole in brain research where very
significant amounts of work is being done round the edge of the
problem but where there is no good model of how electrical pulses in
the brain are translated into human language or behaviour. I have
also discussed at length how work on a highly unconventional language
called CODIL (COntext Dependent Information Language) may throw some light on the issue and recently introduced the
term memode (memory node - see The Evolution of Intelligence - From Neural Net to Natural Langauge) to try and demonstrate a possible
mechanism. However there was still a major gap in the model if it was to serve as an adequate model for understanding how the evolutionary pressures
worked.
So What has Happened???
The trigger to filling the gap came from the
article “Brain
Cells for Grandmother” in this month's Scientific
American, by Rodrigo Quian Quiroga, Itzhak Fried and Christof Koch.
(see also Concept
Cells: the building blocks of declarative memory functions
by Rodrigo Quain Quiroga). This research involved monitoring the
activity of single neurons in the medial temporal lobe of epileptic
patients undergoing assessment prior to surgery. It was observed
that a single cell might respond to different pictures of a single
individual, while remaining inactive when pictures of other people were shown. In one case a neuron was found which responded to three
different pictures of Luke Skywalker, his name (either in writing or
spoken) and interestingly to a picture of Yoda, another character in
the film Star Wars.
One of the problems I was
facing in earlier brain storms was the relationship between the
information in the working memory (called the Facts in CODIL) and the
main memory which contained the items of information and the links
between them. On reading "Brain Cells for Grandmother" the relationship became clear. Information
is stored in the links, and the main memory and the working memory
are one and the same – the difference is that the working memory
is defined by the links which are currently active. I can now tie my model
into the neural network in the brain and the change of viewpoint
provides throws light on the following aspects of the working and
evolution of the human mind..
- The “virtual” information represented when the top neuron in a memode is active is simply the sum of all the subsidiary memodes (recursively) which are linked to the memode. Thus each concept is at the top of a tree of subsidiary concepts. There is no one location where information about a concept is stored.
- The senses trigger bottom up activity in the memodes, the objects we “see,” “hear,” or “smell” being the highest level memodes activated.
- The CODIL Decision Making algorithm maps onto a process in which active memodes can trigger top-down activity in related but initially non-active memodes. (Basically the brain can decide that if “A” and “B” are active “C” should be active.)
- Consciousness (the information we are actively aware of – and equivalent to the Facts in CODIL) is the sum of the information represented at the time by the top active memodes.
- Learning involves the linking of the top active memodes to generate a new higher level memode. (In fact it looks as if deciding what not to learn and what to forget becomes the critical factor than learning in building memories.)
- If we assume that some decisions are made sequentially - with a series of memodes triggered in a predefined order – the model could support at least a simple spoken (i.e. sequential) language. The experience with CODIL being able to handle significant non-trivial information processing tasks is relevant here. This points to an evolutionary tipping point leading to the explosive growth of both language and other special skills.
For more details read on ....
