My Brain is
Full
The human brain is not a computer, but yes, it really does store,
represent and retrieve information!
About two years ago, Dr. Robert Epstein penned an essay for AEON
entitled "The Empty Brain." [https://aeon.co/essays/your-brain-does-not-process-information-and-it-is-not-a-computer] Dr. Epstein is a research psychologist, and
former editor-in-chief of Psychology Today.
In the essay, Epstein started off decrying the modern, casual attempt to
equate the functions of the human brain with modern digital computers. A computer has physical memory representation
and processes information in a manner prescribed by algorithms. The human
brain, in contrast, lacks physically identifiable memory structures, has no
fixed algorithms, and cannot perform the functions attributed to computer
"processing."
In short, his logic amounts to: you can open up a computer and find each
function physically represented. I might
quibble with that, but he has a valid point as he continues to say that the human
brain has no central processor, no "clock," no memory core, and you
cannot find a physical representation of any of the information that the brain
utilizes in its function. So we should stop using terminology appropriate to a
computer in referring to the function of the brain. The article seems to
resurface in social media every 4-6 months, and every time it does so, I get
called in to comment, or get drawn into a discussion of why the basic premise:
"The brain is not a computer" is true, but nearly everything else in
the article is at best, misinformed, and at worst, junk science.
Generally speaking, the first thing that happens in these
discussions is that commenters tend to denigrate the "soft-science" profession
of psychology and the specific qualifications of the author. I like to avoid that, because psychology is a
very useful tool in the neurosciences, it's just that I feel the author has
insulated himself from the "hard-science" findings of
neurophysiology, neurology and neurosurgery.
If Dr. Epstein had had a colleague in Neuroscience read the essay, he
would likely have been told that many of his illustrations and examples of his
premise are incorrect or misleading.
On the other hand, it may be that he felt that the actual
neurophysiological findings were too technical for a lay audience, and he
wished simply to concentrate on the central premise -- the brain is not a
computer - with simple explanations.
After all, he was editor-in-chief of Psychology Today, a publication that
distills psychological research and development into articles with broad appeal
across both the sciences and lay audience.
Such distillation requires that an article be understandable by readers
with an education well below the MD or PhD level, and much scientific rigor and
accuracy can be lost in translation.
Or it may simply be the approach of psychology as a
field. As a neuroscience researcher, I
am interested in the function of the brain -- human or otherwise. Having been trained initially in physiology
& pharmacology, I tend to take a very mechanistic view. I also work with Neurologists and
Neurosurgeons as part of my day-job, and their viewpoint differs from
mine. They may be more mechanism
oriented in some ways (what brain area connects with another; what happens when
I cut in this place; why is this area acting abnormally), and less detail
oriented in others (not necessarily interested in whether this single cell
is connected to another).
Psychology, however, frequently takes a different approach,
concentrating on the external evidence of brain function. Thus, a psychologist would be much more oriented
upon whether a patient can remember a string of numbers than whether those
numbers actually have some form of representation in the brain. This is actually an approach often taken by
modelers who use a "Black Box" nonlinear systems approach to the
brain. For a nonlinear model, it is not
necessary to map every single connection and modulation, but rather to define
the input and output patterns of a given system. From these, it is possible to calculate
nonlinear mathematical solutions which can transform input to output. It's a useful type of model when the actual
detail is so utterly computational complicated that a detailed model is
unworkable using current technology. Epstein's
essay clearly relies on such a conceptual approach, but ignores that fact that
Neuroscientists do know much of the detail of how the brain processes
and encodes information.
I therefore propose that aside from the central premise -- that
the human brain is not a computer -- many of the examples and conclusions in
the essay are biased by the author's own field and approach to brain function
and neglects or ignores experimental evidence to the contrary. As for my secondary concerns regarding the
validity of Dr. Epstein's essay, I will simply state that he should have
consulted colleagues in the more biological/organic corners of the Neuroscience
field before making his claims and formulating his conclusion.
This is actually familiar territory for me. SF congoers who attended the LibertyCon 27
convention in Chattanooga, TN in 2014 may recall a rather heated discussion
involving myself and physicist and SF author Dr. Travis S. Taylor. Guests
tended to gather around the pool in the late evening, and discussion topics
range widely... and wildly. I had been
asked by many people to comment on Taylor's "quantum connection"
theory of the mind. The short form of
the theory is that some of the "unexplainable" phenomena of the mind
(attraction, common interest, prayer/positive thinking, etc.) could be
explained by a quantum connection, and further, Taylor proposed that
neurofilaments and neurotubules in brain cells could serve as
"antennae" to pick up this quantum signal. Taylor's usual explanation for the phenomenon
included the challenge: "Do you like beer?
Why or why not? You can't explain
that. It's unknowable with conventional
science." - my response:
"Yeah, I can pinpoint the preference right down to the specific
molecules making up the taste receptors in the tongue. Anything you propose, I
can explain with conventional physics and Neuroscience." It was a fun and amicable argument, and we
actually concluded that I think his idea of a quantum connection is interesting
and could be true, but largely untestable.
The problem simply being the selection of the wrong examples for his
premise.
Which takes us back to the AEON essay: Dr. Epstein entreats his readers to stop
using a flawed analogy for the function of the human brain; thus, the human
brain is not a computer. However, in the
process, Epstein uses many other flawed analogies to support his conclusion
that there is neither "representation" nor "processing" of information
in the brain. The problem is that while
we may not have a discrete identifiable location for memory storage -- the
truth is that neuroscientists can observe the phenomena of memory processing in
very real ways. Thus the analogies used
to counter a flawed analogy are themselves flawed. The initial premise is correct (within
certain bounds) but his examples and conclusions are faulty.
So let's take this apart:
First, the brain is not a
computer. We actually had this
discussion in a graduate student class yesterday. I agree.
The brain is not a computer - at least, not a digital one. Rather, the brain is closest to an analog
computer, but even that is a flawed analogy.
One of my favorite thought experiments is to consider that the brain
acts as if it were a steampunk analog calculator... but that's a topic for
another blog! [http://teddysratlab.blogspot.com/2011/02/your-brain-on-steampunk.html]
There is no central processing unit, no "memory core", no
"clocks" that synchronize computation steps, and no place in the
brain where one could "open it up and see the information."
The first problem to crop up in the analogy is that one
could counter that it is not possible to "see" a representation of
memory in a computer, either. Absent the
tools to measure current running through semiconductors and resistors, and
charge held in capacitors, it is not possible to see the representation of a
picture or any other information content in a computer. Even then, one does not simply see a color, a
line or an object. Instead, the computer
stores bits--ones and zeros, represented by presence and/or absence of voltage,
current, or charge--and those bits represent other information such as color,
shading, presence or absence of lines or shapes. On its own, the computer representation also
not a "picture," although it can be argued that there is a
discrete storage location for the information.
As for there not being a "representation" of memory
information in the brain, one need only look at the evidence that the visual
and auditory cortex of the brain are organized into groups of brain cells that
only respond to a single visual (i.e. line, rotation, position, color) or
auditory (frequency, movement, location) feature of the respective sense. These are highly topographic mappings of
information onto the structure and function of the brain.
But let's take it one step further: My colleague Jack Gallant at UC Berkeley [https://vcresearch.berkeley.edu/faculty/jack-l-gallant]
would certainly argue that the brain does indeed store and represent a recognizable
pattern for pictures and visual scenes. In
2011, Dr. Gallant published a study in which his team identified brain signals
that corresponded to visual scenes in memory.
Using an MRI scanner to track blood and oxygen usage in the brain at
resolutions down to cubic millimeters of brain tissue, the team created a
"library" of brain activity patterns that resulted when a person
looked at particular pictures. Later,
the same subjects were told to "daydream" a scene involving some or
all of the pictures. Gallant's team was
able to identify a "movie" of the daydream constructed from human brain
patterns. As the subject imagined each scene
in their daydream, the team compared the resulting brain patterns with the
library of patterns correlated with previously viewed images. The identified pictures were placed in
sequence, and compared to the subject's report of their daydream with a very
high correlation between the two. Thus
Gallant and I would argue that here is evidence that the human brain does
both store and represent memory information in the brain.
Unlike a computer, the storage location is not fixed, and
the "storage medium" is not standardized. Still, there are identifiable patterns within
the brain that correspond to the stored--i.e. remembered--information. Furthermore, there is ample evidence that
such information is "processed."
A particular region of the brain, the hippocampus, is
involved in the processing of memory in all species of mammals, with a similar
structure fulfilling the same function in reptiles and birds. Animals and humans with damage to this part
of the brain have difficulty formulating new memories, and may also have
difficult retrieving memories. In 1971,
researchers John O'Keefe and Jonathan Dostrovsky noticed that certain cells in
the hippocampus of rats were active only when the rat was in a particular
position in the cage or test chamber [https://doi.org/10.1016/0006-8993(71)90358-1]. The finding led to nearly 50 years of
research into "place cells" in the hippocampus, which correlate their
activity with various elements of location.
Cells have been identified with preferences to corners, edges, head
directions, body directions, and both future and past movements. The more cells are recorded from a single
subject, the more detailed a "cognitive map" of the environment can
be created from the activity of these neurons.
Furthermore, the "map" may disappear or reorganize when the subject
moves to a new environment, room, chamber or cage, but will reappear in the
original form when returned to the original environment. Thus, a representation of place exists in the
hippocampus, and moreover, it is a memory of a representation, since it
can completely disappear and be re-formed in the original format. Place cells and place fields have been
identified in mice, rats, gerbils, cats, dogs, monkeys and even humans,
demonstrating that this is a function associated with the physical nature of
the brain, and not just an "emergent" phenomenon of human cognition.
In 1994, Matt Wilson and Bruce McNaughton demonstrated that
place cells were not only involved in a physical representation, but that they
were an important component of memory [https://doi.org/10.1126/science.8036517]. Utilizing a track that limited a rat's
movement through the environment to specific lanes--and hence a specific
sequence of activating various place cells, the team demonstrated that the same
cells were activated during sleep in the same sequence as when the
animal had passed through them in the test session. By making the rat's behavior and reward
dependent on remembering a previous sequence of movement, and then manipulating
whether this sleep-replay could occur, Wilson, McNaughton and their colleagues were
eventually able to demonstrate that the replay was an important phase of memory
formation. If the spatial information
was to be remembered, it had to be replayed during sleep!
One of the major questions raised by both the scientists
studying place cells, and the outsiders looking in, was that there was
(evidently) no clock, no map, and no coordinate system driving the representation
of spatial position in the brain. Then
in 2005, Edvard and May-Britt Moser and their teams reported that neurons in
another part of the brain--the entorhinal cortex, which lies
"upstream" from the hippocampus--had neurons which fired in a regular
grid pattern throughout the environment [https://doi.org/10.1146/annurev.neuro.31.061307.090723]. While not a square representation analogous
to the Cartesian coordinates of a world map, the "Grid cells" nevertheless
formed a triangular or hexagonal spatial mapping which could serve as the basis
for the hippocampal place cells!
So, with just a few examples, we shoot down the "no
representation," "no storage," "no controller" and
even the "no processing" portions of the AEON articles premise. In yet another example, of identifying
computer or electronic-like functions of the brain, Dale Purves published an
article in 1996 that began to lend credence to the concept that the human brain
had a function analogous to a CPU clock-cycle [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC39674/]. Most people have viewed a demonstration of
the stroboscopic effect: if a bright light is flashed on a moving object, it
can appear to be still. Photographers use it to create stop-action images that
reveal the wonders of nature: the beat of a hummingbird's wing, popping a balloon,
a drop of water. It is the basic mechanism of a movie film and video. A sequence of images projected in a stroboscopic
manner can create the illusion of motion.
Other illusions are also possible, as seen in the "wagon wheel
effect" in which video of a moving object appears to rotate backward because
the "frame rate" of the video (or the original photography) does not
match the rate of rotation.
Picture a wagon wheel with 12 spokes. If the motion of the wheel is captured
exactly at, say, 4 times the speed of revolution, the spokes will always be in
the same orientation, so playback of those photos makes it appear that the
wheel is standing perfectly still. If
the capture speed is slightly slower, the spokes turn a slight additional
amount with each photo, and the playback looks as if the wheel is rotating
forward. If the capture speed is
slightly faster than rotation, the spokes move less with each capture, and in playback,
the wheel appears to be moving backward.
It's the same principle that caused video of CRT-style computer screens
to have scan lines and dark bands: the screens typically refreshed at 30 or 60
times per second, but pre-HD video capture was at 29.97 times per second.
Purves research demonstrated that even in continuous
light--i.e., no strobes, no frames--the human brain can sometimes perceive a "wagon-wheel
effect." To summarize a lot of further research, the human brain acts
as if it has a 10-times-per-second "frame rate." Furthermore, we know from various
Neuroscience experiments, that the mammalian brain relies on many basic
"rhythms" (at roughly 4, 6, 12, 20 and 40 Hz) that can act similarly
to a clock function for the brain. They
are not quite computer-like, for they are highly variable, and in fact, one of
the key flexibilities of the human brain is the ability to alter certain
rhythms with conscious and unconscious control.
With these examples, we've pretty much shot down the corollary
statements to Dr. Epstein's premise. But
what about his example of the flawed memory of a $1 bill? We know that there are many artists and individuals
who can draw, paint, sculpt and create beautiful detail from memory. This is perhaps the easiest of his
demonstrations to shoot down. The
example shown is simply less effective memory and offers no "proof"
to the lack of representation in the brain, whereas I have provided four very
real examples above--including literature citations--which disprove Epstein's
claims. As stated from the start, his
counter to a flawed analogy is to simply trot out more flawed analogies.
No, the brain is not a computer. It's better! The brain is a wonderful
thing filled with emergent properties and untapped potential. Thinking of it as a computer is... limited...
not flawed. There are many features of
the brain which inspire and direct our current computer technology from parallel
computing, to neural networks, quantum computing and a renewed appreciation of
analog systems.
But to say that the brain is not a computer, and then to
follow that statement with conditions that can easily be disproven by recourse
to experimental evidence outside one's own field is parochial, misguided, and
misleading. We live in a society that
all too often doubts scientific professionals because of the flaws in
communication.
As professionals, we must do better than that.