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Tuesday, February 28, 2017
How Brain Scientists Forgot That Brains Have Owners
It’s a good time to be interested in the brain. Neuroscientists can now turn neurons on or off with just a flash of light, allowing them to manipulate the behavior of animals with exceptional precision. They can turn brains transparent and seed them with glowing molecules to divine their structure. They can record the activity of huge numbers of neurons at once. And those are just the tools that currently exist. In 2013, Barack Obama launched the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative—a $115 million plan to develop even better technologies for understanding the enigmatic gray blobs that sit inside our skulls. John Krakaeur,
a neuroscientist at Johns Hopkins Hospital, has been asked to BRAIN
Initiative meetings before, and describes it like “Maleficent being
invited to Sleeping Beauty’s birthday.” That’s because he and four
like-minded friends have become increasingly disenchanted by their
colleagues’ obsession with their toys. And in a new paper
that’s part philosophical treatise and part shot across the bow, they
argue that this technological fetish is leading the field astray.
“People think technology + big data + machine learning = science,” says
Krakauer. “And it’s not.” He and his fellow curmudgeons argue that brains are special because of the behavior
they create—everything from a predator’s pounce to a baby’s cry. But
the study of such behavior is being de-prioritized, or studied “almost
as an afterthought.” Instead, neuroscientists have been focusing on
using their new tools to study individual neurons, or networks of
neurons. According to Krakauer, the unspoken assumption is that if we
collect enough data about the parts, the workings of the whole will
become clear. If we fully understand the molecules that dance across a
synapse, or the electrical pulses that zoom along a neuron, or the web
of connections formed by many neurons, we will eventually solve the
mysteries of learning, memory, emotion, and more. “The fallacy is that
more of the same kind of work in the infinitely postponed future will
transform into knowing why that mother’s crying or why I’m feeling this
way,” says Krakauer. And, as he and his colleagues argue, it will not.
That’s because behavior is an emergent
property—it arises from large groups of neurons working together, and
isn’t apparent from studying any single one. You can draw parallels with
the flocking of birds. Biologists have long wondered how they manage to
wheel about the skies in perfect coordination, as if they were a single
entity. In the 1980s, computer scientists showed that this can happen
if each bird obeys a few simple rules, which dictate their distance and
alignment relative to their peers. From these simple individual rules,
collective complexity emerges.But
you would never have been able to predict the latter from the former.
No matter how thoroughly you understood the physics of feathers, you
could never have predicted a murmuration of starlings
without first seeing it happen. So it is with the brain. As British
neuroscientist David Marr wrote in 1982, “trying to understand
perception by understanding neurons is like trying to understand a
bird’s flight by studying only feathers. It just cannot be done.” A landmark study, published last year, beautifully illustrated his point using, of all things, retro video games. Eric Jonas and Konrad Kording examined the MOS 6502 microchip, which ran classics like Donkey Kong and Space Invaders,
in the style of neuroscientists. Using the approaches that are common
to brain science, they wondered if they could rediscover what they
already knew about the chip—how its transistors and logic gates process
information, and how they run simple games. And they utterly failed.
“What
we extracted was so incredibly superficial,” Jonas told me last year.
And “in the real world, this would be a millions-of-dollars data set.”
If the kind of neuroscience that has come to dominate the field couldn’t
explain the workings of a simple, dated microchip, how could it hope to
explain the brain—reputedly the most complex object in the universe?
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