Mental models - and how the brain works

Copyright 2016 Graham Berrisford.

One of about 300 papers at http://avancier.website. Last updated 21/04/2017 09:33

Contents

Creating, using and sharing mental models. 1

Current speculations on how memory/thinking works. 2

Encoding memories in engrams. 3

Decoding memories - recall and thinking. 3

How does the brain work - chemically speaking?. 4

How bad is our memory?. 5

How clever are we?. 5

What does this suggest about the mind-body problem?. 5

 

Mind and body

We usually discuss the brain as it appears in human kind.

We think of it as the place in the body where memory, intelligence and self-awareness are located.

But limited kinds of memory, intelligence and self-awareness are evident in primitive life forms

All animals “know” enough about themselves not to eat their own bodies.

Primitive animals are intelligent enough to sense the state of their environment, and respond accordingly.

So, is there no attempt here to separate the brain or mind from the body.

Creating, using and sharing mental models

How do we monitor and influence entities and events in our environment?

Conant’s “good regulator” theorem says we must have a model of those entities and events, however sketchy that model may be.

Regulatory system

Mental models

<create and use>    <abstract concepts from>

Humans   <monitor and influence>  Entities and events

 

A mental model is an idea (be it simple or complex) encoded in the mind about a reality.

We hold mental models of things we perceive now, perceived yesterday, and envisage tomorrow.

A mental model is a partial and flawed description of a reality.

It is an imperfect truth, fuzzy edged, and only accurate enough to help us survive and thrive.

 

This paper goes on to indicate that nobody knows how mental models are stored and maintained.

And it seems nobody is sure if memory and thought are the same or different, inseparable or separable.

Nevertheless, we can legitimately speak of mental models without needing to explain how the brain works.

Because animals clearly do create mental models as side effects of physical sensations and of thinking.

 

The first evidence for mental models is that animals successfully recognise things they have met before.

And then act according to what they remember of their past experience.

The second evidence is that animals successfully share descriptions of realities.

E.g. honey bees tell other bees where the pollen is, and those bees then find it.

 

As social animals, we humans share mental models by sending and receiving communications.

Gesturing animatedly to an oncoming train is enough to share the mental model of that as a threat to survival.

As humans, we translate mental models into and out of verbal forms.

Spoken words translate mental models into transient sound waves – heard by a currently present audience.

Written words transcribe mental models into persistent graphical symbols – readable by future and remote audiences.

Current speculations on how memory/thinking works

It is presumed that memory/thinking evolved to help animals use past entities and events as a guide to future actions.

The mix of proposals and research later in this paper indicate it is likely that:

·         thinking involves continuous electrical impulses and processing of bio-chemicals

·         thinking involves a lot of parallel processing

·         only a fraction of the parallel processing is evident in the stream of consciousness

·         it is difficult to separate memory and thinking (see below)

·         a memory may change as a side effect of thinking

·         there is no meaning in the biological codes of bio-chemicals and electrical impulses per se.

·         a memory becomes meaningful when it is used (perhaps after thinking brings it into the spotlight of conscious thought).

 

Keeping a perfect and complete record of every past entity and event is not necessarily useful or efficient.

So, specific memories may be given up or converted into general knowledge (converted from episodic to semantic memories).

It may well be that we generalize from experience as part of an ongoing recall/re-consolidation process.

And that the fuzziness of mental models is the very quality that enables abstraction from particulars to universals.

 

So remember that our mental models are only sketchy representations of what is out there.

How bad is our memory? Probably worse than you think; see the references in the later section.

How clever are we? Probably not as clever as you think; see the references in the later section.

More happily for this work:

·         We can remember a huge amount of experience and information accurately enough to use it effectively.

·         Remembering events (as opposed to entities) is a human skill that dogs don’t have.

·         A deeper, more abstract way of approaching problems makes experts more successful. (Chi et al. 1981)

 

The remainder of this section is composed of snippets quoted and edited from this resource http://www.human-memory.net

You can check out at the wider resource catalogue (recommended by Adrian Hall) at http://medassisting.org/learning-resources/anatomy/#NervousSystem.

Encoding memories in engrams

Encoding beginning with perception through the senses

It converts a perceived item of interest into a construct that can be stored within the brain, and then recalled later from short-term or long-term memory.

An engram is a memory trace, a hypothetical biophysical or biochemical change in the neurons of the brain; no-one has ever actually seen, or even proved the existence of an engram.

The process of laying down a memory begins with attention (regulated by the thalamus and the frontal lobe) to external stimuli, and creates an engram in response.

A memorable event causes neurons to fire more frequently, making the experience more intense and increasing the likelihood that the event is encoded as a memory.

Although the exact mechanism is not completely understood, encoding occurs on different levels.

The first step being the formation of short-term memory from the ultra-short term sensory memory, followed by the conversion to a long-term memory by a process of memory consolidation.

Decoding memories - recall and thinking

During recall, the brain "replays" a pattern of neural activity that was originally generated in response to a particular event, echoing the brain's perception of the real event.

In fact, there is no real solid distinction between the act of remembering and the act of thinking.

These replays are not quite identical to the original, though - otherwise we would not know the difference between the genuine experience and the memory.

[They] are mixed with an awareness of the current situation.

Memories are not frozen in time, and new information and suggestions may become incorporated into old memories over time.

Thus, remembering can be thought of as an act of creative re-imagination.

 

Memories are not stored in our brains like books on library shelves, or even as a collection of self-contained recordings or pictures or video clips.

[They] may be better thought of as a kind of collage or a jigsaw puzzle, involving different elements stored in disparate parts of the brain linked together by associations and neural networks.

Memory retrieval therefore requires re-visiting the nerve pathways the brain formed when encoding the memory.

The strength of those pathways determines how quickly the memory can be recalled.

Recall effectively returns a memory from long-term storage to short-term or working memory, where it can be accessed, in a kind of mirror image of the encoding process.

It is then re-stored back in long-term memory, thus re-consolidating and strengthening it.

How does the brain work - chemically speaking?

Much (perhaps most?) is still unknown about how the brain works; theories abound.

 

2014 Wikipedia

Long-term memory, unlike short-term memory, is dependent upon the construction of new proteins.

 

2009 Scientific American

Current thinking holds that new memories are encoded in the hippocampus and then eventually transferred to the frontal lobes for long-term storage. .

In other words, the location of a recollection in the brain varies based on how old that recollection is.

 

2014 Paul King:  Computational Neuroscientist, Redwood Center for Theoretical Neuroscience

At the most basic level, memories are stored as microscopic chemical changes at the connection points between neurons in the brain.

The strengthening and weakening of the synapses is how the brain stores information.

From here, the story becomes much more complex.

The precise way that long-term memories are structured and represented across billions of synapses is the subject of intense ongoing research and remains one of the great mysteries of neuroscience.

 

2013 Gerard Marx, MX Biotech Ltd., Chaim Gilon, Institute of Chemistry, Hebrew University, Jerusalem, Israel, ACS Chem. Neurosci., 2013, 4 (6), pp 983–993 February 18, 2013

“We propose a tripartite mechanism to describe the processing of cognitive information (cog-info), comprising the

           neuron,

           surrounding neural extracellular matrix (nECM), and

           numerous “trace” metals distributed therein.

The neuron is encased in a polyanionic nECM lattice doped with metals (>10), wherein it processes (computes) and stores cog-info.

Each [nECM:metal] complex is the molecular correlate of a cognitive unit of information (cuinfo), similar to a computer “bit”.

 

From http://www.human-memory.net/brain_neurons.html

The average human brain has about 100 billion neurons and many more neuroglia (or glial cells).

Each neuron may be connected to up to 10,000 other neurons, passing signals to each other via as many as 1,000 trillion synaptic connections, equivalent by some estimates to a computer with a 1 trillion bit per second processor.

It used to be thought that the role of glial cells was limited to the physical support, nutrition and repair of the neurons of the central nervous system.

Recent research suggests that glial cells actually perform a much more active role, although the extent and mechanics of this role is still uncertain

Estimates of the human brain’s memory capacity vary wildly from 1 to 1,000 terabytes.

(cf. the 19 million volumes in the US Library of Congress represents about 10 terabytes of data).

The processes of memory encoding and retrieval [are] achieved using a combination of chemicals and electricity.

Subtle variations in the mechanisms of neurotransmission allow the brain to [perform] encoding, consolidation, storage and retrieval of memories.

The hippocampus is responsible for analyzing inputs and ultimately deciding if they will be committed to long-term memory.

It acts as a kind of sorting centre where the new sensations are compared and associated with previously recorded ones.

The various threads of information are then stored in various different parts of the brain, although the exact way in which these pieces are identified and recalled later remains largely unknown.

How bad is our memory?

Probably worse than you think.

1.      How Quickly We Forget: The Transience of Memory

2.      Absent-Mindedness: A Blessing in Disguise?

3.      On the Tip-of-the-Tongue: Blocked Memories

4.      How Memories are Distorted or Invented: Misattribution

5.      When Suggestibility is a Liability: Wrongful Convictions

6.      How the Consistency Bias Warps Our Personal and Political Memories

7.      The Persistence of Memory

8.      Our short-term memory lasts only 15-30 seconds (Peterson and Peterson, 1959)

9.      Our long-term memory is unreliable (Implanting False Memories: Lost in the Mall & Paul Ingram)

10.  We miss a lot, because our “The Attentional Spotlight” is highly selective (Cherry, 1953. The Cocktail Party Effect).

How clever are we?

Probably not as clever as you think.

1.      Most of us find formal logic extremely difficult to cope with, fail even simple tests (Wason, 1968)

2.      What we see tends to override what we hear, even if what we hear is right (McGurk and MacDonald, 1976).

3.      We don’t recognise what we are incompetent at (Dunning Kruger effect).

4.      We make irrational decisions (Cognitive bias).

5.      We are strongly influenced by the wording of a proposition put to us (Kahneman and Tversky (1981).

What does this suggest about the mind-body problem?

For Karl Popper (1902–1994) there are three aspects of the mind–body problem: matter (material reality) minds (of actors) and creations of the mind (including descriptions).

The body–mind problem is the question of whether and how our thought processes [in our mind] are bound up with brain events [in our body matter]...

I would argue that the first and oldest of these attempted solutions is the only one that deserves to be taken seriously [namely: mind and matter interact].

— Karl Popper, Notes of a realist on the body–mind problem.

 

For John Searle (b. 1932) the mind–body problem is a false dichotomy; that is, mind is a perfectly ordinary aspect of the brain.

There is no more a mind–body problem than there is a macro–micro economics problem; they are different levels of description of the same set of phenomena.

But Searle is careful to maintain that the mental – the domain of qualitative experience and understanding – has no counterpart on the micro-level.

— Joshua Rust on John Searle.

 

Cognitive science is increasingly interested in the embodiment of human perception, thinking, and action.

Proponents of this approach [hope it will dissolve] the Cartesian divide between the immaterial mind and the material existence of human beings (Damasio, 1994; Gallagher, 2005).

The shape, timing, and effects of [bodily actions such as pressing a button] are inseparable from their meaning.

— Georg Goldenberg, "How the Mind Moves the Body: Lessons From Apraxia" in Oxford Handbook of Human Action

 

The presumptions here are as follows.

The body is the entirety of an organism that is located spatially in a wider environment.

The brain is a body part specialised in monitoring what exists/happens in the environment, holding mental models and directing bodily actions.

The mind is that part of an organism that can form, remember and use bio/electro/chemically encoded forms of perceptions, memories, descriptions and directions.

The mind may primarily reside in the brain, but other parts of the body can be involved in mental processes.

Humans create and use concepts (encoded in the brain, on paper, or other) to describe and predict what exists/happens in that environment.

Where exactly the description of a concept is located inside the body is not important to the philosophy here.

Somehow, some way, the concept is encoded in the matter and energy contained within the body

And it doesn’t matter to us if that “somehow” proves forever obscure, incomprehensible and indescribable.

 

 

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