I get a lot of questions in Quora
about neuroscience, because neuroscience is what I do. A recent question
prompts this post. The question was: "Does all thinking originate in subconscious
thinking?" This is a provocative question. It gets to the heart of the
matter: What is the default mode of brain operation, conscious or subconscious?
Semantic Confusion
Much of the confusion about consciousness arises because words
fail us. We have poor definitions for the usual words: conscious, unconscious,
subconscious, non-conscious. Before I attempt an answer to my Quora
question, let me establish some background about terminology. First, the
currency of thought is patterns of nerve impulse activity constrained by
flowing in and through defined circuits of linked neurons. The impulse thought
patterns that occur in primitive circuitry, like spinal segments and neuroendocrine circuits are
considered nonconscious thoughts because we can never be consciously aware of
what those circuits are doing. We can, for example, use instruments to measure
our blood pressure, but on its own, the brain can never detect that
consciously.
Perhaps the most common kind of thought is that which
occurs all the time, even when asleep, that we are not aware of. These days, scholars
like to call this "unconscious" thinking. But coma is clearly an unconscious state, and
there often is little electrical activity that reflects thought. That is why a
more useful term in this context is "subconscious," a term
popularized by Freud. That is probably why the term has fallen into disuse. Too
many of Freud's ideas have been discredited. But not his idea of
subconsciousness.
Consciousness Is Not the Same as Being Awake
Reflect on your own perceptual experiences.
Every time you are consciously aware of something you were attending to it.
True, you can be awake without being conscious (see Selective Attention below).
This means that we have to make a careful distinction between wakefulness and
consciousness. They are not synonymous. You can't be conscious if you are not
awake, but being awake does not assure consciousness of non-attended objects. Wakefulness is generated out of excitatory
activity of the brainstem reticular formation acting on neocortex, as I explain
in my book, Mental Biology. The
mechanisms of consciousness have not been established, but they likely involve
coherent nerve impulse activity in distributed circuitry.
The phylogenetic perspective argues for
unconsciousness as the default mode of thinking, inasmuch as lower animals are
not likely to have conscious thought, yet their behavior clearly indicates that
they are awake and their brains are "thinking." Also, we know from
studies of infants that behavioral signs of consciousness are rare and only
emerge as the brain matures. It is clear that much human thinking occurs below
the level of conscious awareness.
The many scholars who claim that humans have
no free will use the assumption of subconscious thinking to defend their stance
against free will. They came to this conclusion from experiments that say
indicate that all willed action is generated subconsciously and only recognized
later in consciousness. The experiments and the interpretation are flawed, as I
explain in my book on free will. To help defend the stance that free will is an
illusion, the proponents go further to argue that consciousness is just an
observer, like a movie patron in a theatre. You can just watch what is
happening but can't do anything about it. Thus, they construct the specious
circular argument that you can’t have free will because free will requires
consciousness by definition, and consciousness can’t do anything. How convenient!
This absurd notion, held by academics who are not as smart as they think they
are, assume that all our consciousness thinking is basically irrelevant. They
assume that the neural activity of conscious thought cannot influence neural
activity in other parts of the brain, even though they have to admit that the
neurons that mediate conscious thought are functionally connected with the
other parts of brain. By these connections, conscious thought can, for example,
explicitly evaluate the meaning of stimuli, or order certain muscles to
contract, or force mental effort to memorize,
or change our emotional state and visceral functions in light of reason or
mindfulness meditation, and so on. The circuitry of consciousness is not in a
pickle jar outside the brain. It is inextricably bound to other brain circuits.
I certainly don't mean to dignify the
anti-free-will position by describing it. However, debunking that position
opens the door to reconsider the possible relationship between subconscious and
conscious thought. Suppose conscious thought is an afterthought, but not in the
restricted sense prescribed by the anti-free-will crowd. Just because
subconscious thought can lead to conscious thought does not mean that conscious
thought has no action of its own. When we consciously think about what we have
recognized in consciousness, all that thinking is, by definition,
conscious. Conscious thought can
consider options explicitly. It can reason. It can set goals, plan, command
action, evaluate consequences of action, and adjust programming as needed.
Subconscious thinking can do that too. Most likely the two modes of thinking
work in potentially synergistic ways, though it seems clear that conscious
thought can veto subconscious impulses and bad ideas.
Consciousness as Selective Attention
Have you seen the U tube video of a pickup
basketball game? The video instructs viewers to count how many times one of the
teams pass the ball. Viewers are so focused on the task that many of them fail
to see a man in a gorilla suite walk into the game, do a little chest pounding,
and then walk off the court. The point is that the eyes and subconscious mind
saw the gorilla, but not the conscious mind. The same phenomena has been
confirmed in another context. The phenomenon is labeled by psychologists as
"inattentional blindness." In other words, we are only conscious of
targets of our attention.
Like all biological systems, brains are stimulus-response
systems. Humans have unique ways to respond to stimuli and experience, in that their
brains selectively identify the information content, evaluate it in terms of
available optional responses, and then determines an appropriate response. Both
subconscious and conscious thought can be involved, but conscious thought only
operates on attended targets.
Scanning for Meaningful Impulse Patterns
While it is clear that conscious brains
think, it may be useful to consider that consciousness is also a scanning
mechanism. We don't know how such scanning is enabled by wakefulness, but we do
know that the awake brain generates more regular oscillations of impulse
activity. These oscillations arise in many localized subnetworks throughout the
cortex, occurring at varying frequencies and extent of synchrony among other
generators. Intracellular recordings of neurons reveal that one or a few spikes
are generated each time the membrane depolarizes. Oscillation is a built-in
feature of neural circuits which commonly oscillate because impulse output
re-enters the circuitry that generates it.
Increasing the frequency of oscillation increases the total impulse
discharge because there are more depolarizations per unit of time. This
increases the informational throughput in the network. Likewise, the degree to
which multiple oscillators synchronize to share data modulates impulse
throughput throughout linked circuits.
Perhaps the oscillation itself is the
scanning mechanism. As novel or particularly relevant input enters an
oscillating circuit, that circuit’s own impulse firing pattern may be
disrupted, re-set, change frequency, or alter its time locking to other
subnetworks. Enhanced time-locking among circuits could have the magnifying
intensity effect that seems to be required in selective conscious attention.
The carrying capacity for information is limited, because only subsets of
networks in the global workspace synchronously engage at any one moment. This is
one way to improve the signal-to-noise ratio of neural circuit processing.
Perhaps conscious thought is the afterthought
of this scanning once it latches onto a subconscious thought that compels
attention. Such a mechanism has great biological advantage in that it is a way
for brain to scan through a noisy stimulus- and thought-world to identify
signals that are salient for appropriate and selective processing and response.
Once the target is captured in consciousness, conscious neural activity
evaluates the salient signals and determines what to do about it and directs
useful action. Taken in this light, I answer a tentative yes to my Quora
questioner who wanted to know if all thinking originates in subconscious
thinking.
Sources
Klemm, W. R. (2014). Mental Biology: The New
Science of How the Brain and Mind Relate. New York: Prometheus.
Klemm, W. R. (2016). Making a Scientific Case
for Conscious Agency and Free Will. New York: Academic Press.
https://www.youtube.com/watch?v=vJG698U2Mvo The original basketball game example of the
invisible gorilla.
https://www.youtube.com/watch?v=UtKt8YF7dgQ A confirmation of the invisible gorilla in
another context.