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Humans like to think of ourselves as special.
We point to how smart we are, how many wrinkles our brains have,
and our unique brain regions to show just how different we are from animals.
And other animals’ brains?
Totally an insult.
Calling someone a “birdbrain” is the height of wit, probably.
But it’s long past time to retire that one.
Because studying bird brains isn’t just showing us how smart birds can be.
It’s challenging old ideas of how smartness evolves in the first place,
as well as just how unique humans really are.
Various human cultures have observed the smartness of corvids
(birds like crows, ravens, and jays) for a long time.
It’s just taken science a little bit to catch up.
It’s hard to test the intelligence of animals that can’t communicate with humans,
so we have to interpret their behavior to get a sense of what’s going on in there.
One of those is tool use.
Scientists define tool use in terms of using an external object to physically
interact with something and change it in some way,
or get information about the environment.
So things like using a leaf to get ants out of a hole in a log,
or using a stick to scratch an itch.
And with that definition, tool use isn’t something all animals do,
but it’s not totally uncommon.
There have been reports of birds doing this kind of thing since at least the 1930s.
But some birds, much like primates, take it one step further.
They don’t just use tools, they manufacture and combine tools.
In a study published in 2002, researchers in the UK
watched a New Caledonian crow make her own tool to lift a bucket.
The crows in the study had been choosing between a hooked wire
and a straight wire to pick up a bucket of food.
But when one of the other birds stole the hooked wire (rude),
this little genius took the straight wire and bent it into a hook.
She made her own, more efficient tool.
And in a 2018 paper, researchers put food in a box and
taught crows that they could use a dowel to push food out.
Then, they took away the dowel and gave them objects that were
too short to reach the food on their own.
But put them together and you could achieve the same effect.
And half of the birds figured that out.
The researchers figure making tools like that may require
higher cognitive abilities like planning and task coordination.
In fact, most modern humans don’t start to show tool innovation skills
until they’re between ages five and nine.
Most impressive of all, crows may even exhibit consciousness.
Consciousness in this sense means not just experiencing something,
but being aware that you’re experiencing it, something that historically
we’ve only thought humans and a few other mammals can do.
In a 2020 paper, researchers in Germany
showed two carrion crows a bunch of shapes.
Sometimes the shapes were bright and easy to see.
Sometimes they were dimmer and right at the edge of
what the crow could see, and other times, nothing was visible at all.
The crows were trained to give a couple responses.
Sometimes they would say “yes I can see the thing”
while other times they were supposed to respond when they could not see it.
But the real key was what was happening in the crows’ brains.
The term neural correlates of consciousness refers to the neuron activity
required for a conscious experience, and only that specific conscious experience.
Scientists study the neural correlates of consciousness by
looking for brain activity that’s different when someone reports
being aware of some stimulus, versus when they don’t.
Now, here’s the key to this research.
When you get right at the edge of what brightness you’re capable of seeing,
sometimes you’ll see the shape, and sometimes you won’t.
So the researchers weren’t so much looking for
whether the crows’ brains saw the shape.
They were looking for whether the crow was going to say if they saw it.
Certain neurons in the crows’ brains had a bigger response when the crow was
going to say they did see the shape, whether or not it had actually been
on the screen, versus when they were going to say they didn’t see the shape,
even if it had actually been there.
So scientists think those neurons that say
“yes I saw something” are a neural correlate of consciousness.
There is some debate over this, but neural correlates of consciousness
typically involve the cerebral cortex, specifically with the prefrontal cortex.
The prefrontal cortex is the very front part of mammals’ brains that’s
critical for complex functions like attention, impulse control, and flexibility.
But bird brains don’t have the right structure to
count as a prefrontal cortex in the traditional sense.
Instead, the neurons in the crows’ brains were
in the nidopallium caudolaterale, or NCL.
Anatomically, it looks really different from the PFC.
But functionally, the two regions seem to have similar functions.
Much like the PFC, the NCL receives signals from sensory areas and sends out
signals to the motor parts of the brain, and plays a role in making decisions,
assigning value to things, working memory, and understanding numbers.
One scientist in the 1990s compared it to computers:
Macs and PCs are wired differently and process things differently,
but in the end they serve the same purpose and do the same things.
Because they’re so different, it’s really unlikely that this type of intelligence
and brain connectivity evolved before birds
and mammals split apart 320 million years ago.
Instead, similar evolutionary pressures may have led to the NCL
and PFC evolving totally separately.
So for animals in multiple niches, there was so much value in
developing consciousness that brains ended up
getting to the same capabilities, just in different ways.
And not just primates and crows.
Cephalopods like octopuses are also super smart, also show behaviors that
look like consciousness, and also have brains that are
completely different from mammals or birds.
So these behaviors and functions might have
evolved totally separately at least three times.
Which means humans might not actually be all that exceptional after all.
And that’s good news, though, because it means there are even more animals
to study to understand how our super smart brains developed (and theirs, too).
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