In 2005 I was waiting for the bus, wondering about
consciousness, and doodling on the back of a journal article I had printed out.
In doing so, I convinced myself that the stream of thought can be described by
a single line that loops every few centimeters. A rational line of reasoning
that stays on topic would loop and then continue to run in the same direction
(vector) that it was in originally. A series of loose associations, on the
other hand, would exit the loop at an unpredictable tangent and start off in a
new direction, irrespective of the direction of the line before it. In this
model, the direction of the line indicated the direction of the stream of
thought. Thus a line that continues in the same direction will progress toward
a goal, whereas a line that is constantly changing directions might be making
interesting new associations, but has no long-term intention or goal. The
pictures below illustrate the difference between these two strategies or modes
of operation.
This idea, and these doodles, strongly influenced my understanding
of the thought process. It went on to influence my model of working memory and
consciousness (Reser, 2011; 2016). However, I never wrote anything about it or
elaborated on it. Let’s do so here. Specifically, let’s consider this model
relative to the current cognitive neuroscience of working memory, and my 2016
model of the stream of thought.
A line that loops is changing course, and experiencing a
detour, perhaps fleshing out a related problem. This means that the items or
representations coactive in the focus of attention have changed and are
iterating though a different scenario. But if after the loop the line of
thought regains its original course then it will return to the items it was
previously holding and continue to iterate. The detour (loop) may have
introduced important new representations that will help it towards its goal.
For example, you may be thinking about what will be involved on your bus trip
to another city. Once you board the bus in your imagination you realize that
you have to pay and you model what it will be like to purchase a ticket to
ride. Your interaction with the bus driver, and your wallet pulls you away from
your thoughts about the trip itself. Now you could forget about the trip and go
on thinking about your wallet, how old and worn it is getting, and what kind of
wallet you want to replace it with. This would involve a change of course for
your vector, or line of thought. Or you could imagine yourself paying the fare
and resuming the next step related to your trip, such as finding out where you
need to get off. This would involve your line of thought looping around another
set of mental representations, but then returning to the original
representations (bus, trip, destination, etc.).
Working memory is thought to have two major components: 1)
the focus of attention, and 2) the short-term store. As you transitioned from
thinking about your trip, to thinking about paying the fare, and then back to
thinking about the trip again, the items related to thinking about the trip
were transferred between stores. They would have gone from the focus of
attention, to being saved temporarily in the short-term store, and then back
into the focus of attention. In other words, the short-term store is a holding
depot for lines of thought that are deemed to be important that we may need to
return to. If instead, you had just kept thinking about your wallet, that would
not have necessitated the short-term store and would have amounted to a loose
association with no associative connection to the recent past. Schizophrenia,
Alzheimer’s and many other brain disorders are characterized by a reduction in
the capacity and duration of the short-term store, and that is why thought is
often constantly derailed in people that have them.
In my 2016 model of working memory (Reser, 2016) I use uppercase letters
to denote items of thought. When two successive thoughts share a large amount
of content they share a large proportion of letters (e.g. thought one = A, B,
C, D and thought two = B, C, D, E). When two successive thought share less
content, they share fewer letters, and thus carry less continuity (e.g. thought
one = A, B, C, D and thought two = D, C, E, F). In the first example above the
two states shared most of their active representations in common (B, C, and D).
In the second example though, the two states only shared one common
representation (D). The next figure applies this general model to the
discussion about lines and loops discussed earlier.
As you can see the first figure uses a single new
representation introduced by each loop, but then returns to A, B, and C. This
represents a prolonged process of thinking about the same concepts in
different, connected contexts. In the second figure none of the concepts under
consideration are maintained after the loop. There is still continuity between two
states, but not between three states. This is clearly more chaotic. I think
that these two modes of operation represent two sides of a continuum. I think
they corresponds to type one (Kahneman’s thinking fast), and type two (thinking
slow), with intermediate rates of updating between the two.
What do you think? Can you see how thought might be taking
constant detours, that temporarily interrupt continuity, so that it can
introduce new content to the line of persistent content? Do you ever notice
that your train of thought breaks away for a few seconds only to comeback more
inspired and informed? How about the opposite. Can these respites and detours
be distracting?
Reser, J. 2016. Incremental change in the set of coactive cortical
assemblies enables mental continuity. Physiology and Behavior.
167: 222-237.
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