I want to pass on this nice brief
essay by David Eagleman:
For centuries, neuroscience attempted to neatly assign labels to the
various parts of the brain: this is the area for language, this one for
morality, this for tool use, color detection, face recognition, and so
on. This search for an orderly brain map started off as a viable
endeavor, but turned out to be misguided.
The deep and beautiful trick of the brain is more interesting: it
possesses multiple, overlapping ways of dealing with the world. It is a
machine built of conflicting parts. It is a representative democracy
that functions by competition among parties who all believe they know the right way to solve the problem.
As a result, we can get mad at ourselves, argue with ourselves, curse
at ourselves and contract with ourselves. We can feel conflicted. These
sorts of neural battles lie behind marital infidelity, relapses into
addiction, cheating on diets, breaking of New Year's resolutions—all
situations in which some parts of a person want one thing and other
parts another.
These are things which modern machines simply do not do. Your car
cannot be conflicted about which way to turn: it has one steering wheel
commanded by only one driver, and it follows directions without
complaint. Brains, on the other hand, can be of two minds, and often
many more. We don't know whether to turn toward the cake or away from
it, because there are several sets of hands on the steering wheel of
behavior.
Take memory. Under normal circumstances, memories of daily events are
consolidated by an area of the brain called the hippocampus. But in
frightening situations—such as a car accident or a robbery—another area,
the amygdala, also lays down memories along an independent, secondary
memory track. Amygdala memories have a different quality to them: they
are difficult to erase and they can return in "flash-bulb" fashion—a
common description of rape victims and war veterans. In other words,
there is more than one way to lay down memory. We're not talking about
memories of different events, but different memories of the same
event. The unfolding story appears to be that there may be even more
than two factions involved, all writing down information and later
competing to tell the story. The unity of memory is an illusion.
And consider the different systems involved in decision making: some
are fast, automatic and below the surface of conscious awareness; others
are slow, cognitive, and conscious. And there's no reason to assume
there are only two systems; there may well be a spectrum. Some networks
in the brain are implicated in long-term decisions, others in short-term
impulses (and there may be a fleet of medium-term biases as well).
Attention, also, has also recently come to be understood as the end
result of multiple, competing networks, some for focused, dedicated
attention to a specific task, and others for monitoring broadly
(vigilance). They are always locked in competition to steer the actions
of the organism.
Even basic sensory functions—like the detection of motion—appear now to
have been reinvented multiple times by evolution. This provides the
perfect substrate for a neural democracy.
On a larger anatomical scale, the two hemispheres of the brain, left
and right, can be understood as overlapping systems that compete. We
know this from patients whose hemispheres are disconnected: they
essentially function with two independent brains. For example, put a
pencil in each hand, and they can simultaneously draw incompatible
figures such as a circle and a triangle. The two hemispheres function
differently in the domains of language, abstract thinking, story
construction, inference, memory, gambling strategies, and so on. The two
halves constitute a team of rivals: agents with the same goals but
slightly different ways of going about it.
To my mind, this elegant solution to the mysteries of the brain should
change the goal for aspiring neuroscientists. Instead of spending years
advocating for one's favorite solution, the mission should evolve into
elucidating the different overlapping solutions: how they compete, how
the union is held together, and what happens when things fall apart.
Part of the importance of discovering elegant solutions is capitalizing
on them. The neural democracy model may be just the thing to dislodge
artificial intelligence. We human programmers still approach a problem
by assuming there's a best way to solve it, or that there's a way it should
be solved. But evolution does not solve a problem and then check it off
the list. Instead, it ceaselessly reinvents programs, each with
overlapping and competing approaches. The lesson is to abandon the
question "what's the most clever way to solve that problem?" in favor of
"are there multiple, overlapping ways to solve that problem?" This will
be the starting point in ushering in a fruitful new age of elegantly
inelegant computational devices.
IBM's Watson implements that conflict solution.
ReplyDeleteSeveral experts (algorithms) compite to find the "best solution". So there is anymore "the solution"
The system learns what algorithm does better in everycase.
A human aproach in IA.