I came across the following headline that immediately caught my attention: "Crows Are Capable of Conscious Thought, Scientists Demonstrate For The First Time." This was an article by Michelle Starr (ScienceAlert.com, Sept 2020) and it starts out with the following paragraph:
"New research into the minds of crows has revealed a jaw-dropping[1]
finding: the canny corvids aren't just clever - they also possess a form of
consciousness, able to be consciously aware of the world around them in the
present. In other words, they have subjective experiences."
This was intriguing enough to force me to read the original paper referenced in the
article: "A neural correlate of
sensory consciousness in a corvid bird" by Andreas Nieder, Lysann Wagener,
and Paul Rinnert from the University of Tubingen, Germany; and published in
Science in September 2020.
This study
is interesting not only due to the hype (or, really, in spite of the hype), but
also due to the methods used and the fact that crows can be trained to do a
task that is pretty complicated. I
learned something new about crows. If
you are interested in this topic, it is worth reading. But I will also say that the paper is
difficult to read and understand. In my
opinion, the methods and data could be presented in a more easily understandable
way. I will try, as succinctly as I can,
to describe the experiment performed and highlight the key finding.
The first
thing to note is that the study was performed with two well-trained crows that
were tested over many days. They were
trained to stick their heads into a darkened box where they could see a small
screen where different symbols and colors were presented to the crow. The crow
had to respond to what it saw according to some rules it had learned. For example, one of the tests involved
showing a white square on the screen and the crow had to indicate that it saw the
square by first holding its head in place for a couple of seconds and then
moving its head out of the box. The
crows were also outfitted with a device that recorded the neural activity from
a specific region of the crow's brain - a region where the investigators
hypothesized that "sensory consciousness" resides for the crow. There are many more details to this
experiment, but I think it is possible to gain a basic understanding of the key
finding without going further into the experimental details.
The crux
of the test was this: there is a low
level of light intensity at which the crow sometimes perceives the light and
sometimes does not. This is called the
"threshold of detection" and is something you are familiar with even
if you aren't familiar with the term. For
example, there is a level of sound that, when presented to your ears, you would
say you heard it about half the time.
The same is true when you are touched with a very fine wire. Sometimes
the wire touches your skin and you don't feel it, and sometimes you do. So, in the same way, sometimes the crow
perceived the low level of light that was presented on the screen and indicated
that it saw it, and sometimes the crow didn't perceive the light and therefore indicated
that it didn't see it. Thus, the exact
same intensity of light is put on the screen and sometimes the crow perceives
the light and sometimes it does not. This
kind of "unpredictable" behavior is a common characteristic of complex
living things, but not generally a characteristic we ascribe to machines
(although see next paragraph). If you
had an electronic light detector instead of a crow, presumably it would always
read the same output based on the intensity of the light. Machines don't have a "perception"
where sometimes they see the light and sometimes they don't. How can crows (or any living thing) exhibit "perception"? The assumption of the investigators is that
there must be somewhere in the crow's brain that decides whether it perceived the light or not. Or - to use the word I would rather not use
in this case - crows were sometimes "conscious" of the light and
sometimes not.
In
summary, what you have is an entity that, when presented with the same input,
gives a different output. By itself,
this is not all that surprising. The
electronic circuit device called a "flip-flop" does the same
thing. A flip-flop is a circuit
component that, when presented with an input, gives a different (alternating)
output every time. Kind of like clicking
a ballpoint pen. You click it once and
the ballpoint is out. You click it again
and the ballpoint goes back in. So, by
itself, a changing output with the same input is interesting, but hardly
represents consciousness (unless a flip-flop or ballpoint pen is conscious!).
The reason
the flip-flop changes output each time is because each input causes it to
change its state in preparation for the next
input. Thus, although you have the same
input each time, you do not have the same "state" of the
machine. If you had some entity that
stayed in the exact same state every time, yet still responded with a different
output for the same input, then that would be more interesting. Yet even
that type of entity could hardly be described as "conscious." For example, a true random number generator meets
this latter description. Assuming a
random number generator has no memory of past events (it shouldn't), it will
give a different output every time you make a request (i.e. the same input),
yet presumably it is always in the same state.
And, like a ballpoint pen, random number generators are also not
conscious.
In the
case of the crow experiment, there is no way to eliminate either of these two
conditions and thus, in my opinion, the claim of "consciousness" in
this case is very premature (i.e.
wrong). In fact, although I find the
results of the paper interesting, I believe that the Discussion section of the
paper devolves into baseless claims and hype.
If I had been a peer-reviewer of this paper, I would not have allowed
the authors to make statements like: "Our finding provides evidence for
the phylogenetic origins of consciousness.
It excludes the proposition that only primates...are endowed with
sensory consciousness". Let me
explain why I say this.
First, the
crow's brain could simply be a "complex flip-flop." By that I mean that there is no guarantee
that the crow is in the same state every time the same low-level of light is
presented to it. In fact, given that
crows have memory, this experiment could be simply demonstrating memory
effects. The decision as far as
detection or non-detection of the low threshold light could be totally
dependent on the previous trials or even the overall state of the crow. The authors did not analyze this at all,
which seems like a major oversight. It
could be that the presentation of the previous trial (or trials) is a better
predictor of the crow's response than the neuronal output. But even if that is not the case, the crow's
response could clearly be a product of past responses and the crow's state of
mind. The authors claim that the crow
makes a different choice when presented with the same stimulus. But, in every trial, the "crow" is,
in reality, a slightly different crow.
It is, at the very least, a few seconds older. Further, other things are happening to the
crow besides just getting older. The
most obvious is the presentation of the prior experimental stimuli, but there
are any number of other inputs to the crow's system. The crow is getting a reward after each
trial, and surely the motivation with respect to the reward must change from
trial to trial. And who knows what other
things affect crows? None of these
things were controlled for or ruled out.
And memory effects alone are not sufficient to demonstrate
consciousness. Ballpoint pens have
memory.
Second,
the experimental outcome could be explained by a random process within the
crow's brain. By this I mean that even
if you did a more careful experiment and could measure the "state of mind"
of the crow at each moment, these results could still be explained by a random
number generator. I think it is unlikely that there is a true random
number generator in the crow's brain, but I think it is very likely that the transmission of action potentials across a
synapse at the transmission threshold has a small random component to it. There is nothing in this experiment, as it
was designed and presented, that precludes such an explanation of the data. And random processes are also not conscious.
To be fair
to the authors, they did not design the experiment to demonstrate consciousness
but rather to demonstrate what is called the "neural correlate of
consciousness". That means they
were looking to show what part of the brain, if any, contained the
"perception" effects that the crow demonstrates. In that sense, the experiment is
observational and is certainly not designed to explore the mechanism of action
of consciousness. What the experimenters
observed is that some neurons in a specific area of the cortex of the crow's
brain increase their firing when the crow perceives that it saw a low level of
light, even if there was no light delivered.
So, you could claim that these neurons are responsible for the
perception. But the experiment is not designed to explain how it is that a neuron, or group of
neurons, makes a decision that is in some way independent of its inputs. In fact, that's way beyond the scope of any scientific experiment at present and
strays into the difficulty with "free will" experiments that I have discussed elsewhere.
Finally, "sensory
consciousness", as defined by neuroscientists and as used in this paper,
is not real consciousness as you and
I would think of consciousness. I will
deal with this issue in a future entry. The
authors of the paper are clear about this limitation and acknowledge this point
in their paper. But, of course, that minor little point gets lost when the
reporter for ScienceAlert picks it up.
Suddenly, the outcome of the paper becomes "crows are conscious
like humans." So, we start off with
a paper that doesn't even show "sensory consciousness" in any
conclusive manner and end up with a claim that it shows real human consciousness.
That's called hype! The paper is
interesting, but it in no way shows that crows are conscious. Don't believe the hype.
[1]Whenever
I hear the word "jaw-dropping", I am immediately 99.9% skeptical of
all words that follow. It is the red
flag of red flags that indicates what you are about to read is over-hyped to
the extreme.
