Your brain hallucinates your conscious reality | Anil Seth | TED
Summary
TLDREl discurso explora cómo la conciencia se genera a partir de la actividad neuronal en el cerebro y cómo esta esencia nos hace conscientes de nuestro entorno y nuestra propia existencia. A través de ejemplos como la ilusión de la mano de goma y la realidad virtual, el orador argumenta que nuestras experiencias conscientes son en realidad 'alucinaciones controladas' que surgen de los procesos predictivos del cerebro. Esto tiene implicaciones profundas para la comprensión de la salud mental, la inteligencia artificial y nuestra conexión con la naturaleza.
Takeaways
- 💉 La consciencia puede desaparecer por completo durante la anestesia, lo que contrasta con la sensación de confusión pero de continuidad que se tiene al despertar de un sueño profundo.
- 🧠 La consciencia es un misterio en la ciencia y la filosofía, pero el entendimiento de cómo ocurre es crucial ya que constituye nuestra experiencia del mundo y del yo.
- 🤔 La inteligencia y la consciencia son conceptos distintos; no se necesita ser inteligente para sufrir, pero se necesita estar vivo para tener consciencia.
- 🧪 La investigación sugiere que la consciencia está más relacionada con la naturaleza biológica de los seres vivos que con la inteligencia pura.
- 🌐 Nuestra percepción del mundo es una especie de alucinación controlada generada por el cerebro, que depende tanto de la información sensorial como de las predicciones internas.
- 👀 La ilusión visual muestra cómo el cerebro utiliza expectativas previas para interpretar la información sensorial, como en el caso de las manchas de gris que parecen tener diferentes tonos.
- 👂 El cerebro puede cambiar rápidamente nuestras experiencias conscientes, como se demuestra en el ejemplo del audio distorsionado que se entiende como palabras después de escuchar una pista guía.
- 🤲 El ilusionismo de la mano de goma muestra cómo el cerebro puede incluir objetos externos como parte del cuerpo propio basándose en la congruencia de la visión y el tacto.
- 💓 La experiencia de ser un ser viviente está arraigada en los mecanismos biológicos que nos mantienen vivos, más que en la simple detección de objetos.
- 🧬 Nuestra forma de ser conscientes es única pero está basada en mecanismos biológicos compartidos con otras criaturas, lo que nos conecta con la naturaleza y abre nuevas perspectivas en la comprensión de la consciencia.
Q & A
¿Qué es la anestesia y cómo afecta la conciencia?
-La anestesia es un tipo de magia moderna que puede transformar a las personas en objetos y, con suerte, de regreso a personas. Durante el proceso de anestesia, la conciencia se pierde completamente, lo que representa una de las mayores misterios en la ciencia y la filosofía.
¿Cómo describe el hablante la experiencia de despertar de una anestesia?
-Al despertar de una anestesia, no hay una sensación de tiempo transcurrido o continuidad, a diferencia de lo que ocurre al despertar de un sueño profundo. La persona simplemente no estaba presente, experimentando una total olvidación.
¿Qué es la conciencia según el hablante y por qué es importante entenderla?
-La conciencia es la experiencia consciente que cada uno de nosotros tiene, y es fundamental para la comprensión de nuestro mundo y del yo. Es importante entenderla porque la conciencia es todo lo que tenemos, y sin ella no hay nada.
¿Qué relación hay entre la conciencia y la inteligencia según el discurso?
-La conciencia y la inteligencia son cosas muy diferentes. No se necesita ser inteligente para sufrir, pero probablemente se necesite estar vivo para tener conciencia.
¿Cuál es la teoría del hablante sobre cómo la conciencia se genera?
-La conciencia se genera a través de la actividad combinada de miles de millones de neuronas en el cerebro, cada una generando una experiencia consciente que es única para cada individuo.
¿Qué es el motor de predicción y cómo está relacionado con la percepción?
-El motor de predicción es la idea de que el cerebro utiliza señales sensoriales junto con expectativas previas para hacer su mejor suposición sobre lo que está causando esas señales. Esto significa que la percepción no depende solo de señales entrantes, sino también de predicciones perceptivas que fluyen en la dirección opuesta.
¿Cómo explica el hablante el efecto de la ilusión de la mano de goma?
-El efecto de la ilusión de la mano de goma se debe a que el cerebro combina la visión, el tacto y la ubicación de una mano de goma con la apariencia de una mano, lo que lleva al cerebro a suponer que la mano de goma es parte del cuerpo.
¿Qué es la interoceptiva y por qué es importante para la conciencia?
-La interoceptiva es la percepción de los estados internos del cuerpo, como la condición del corazón o la presión arterial. Es importante porque ayuda a controlar y regular el estado interno del cuerpo, lo que es esencial para la supervivencia.
¿Cómo se relacionan las experiencias del cuerpo interno con la conciencia del yo?
-Las experiencias del cuerpo interno están profundamente enraizadas en la percepción de nuestro cuerpo desde dentro, y son fundamentales para mantenernos vivos. Estas experiencias no se perciben como objetos, sino más como la forma en que el cerebro controla y regula nuestro estado interno.
¿Qué tres implicaciones finales presenta el hablante sobre la conciencia?
-Las tres implicaciones son: 1) Podemos malinterpretar el mundo y a nosotros mismos cuando los mecanismos de predicción fallan, lo que abre nuevas oportunidades en psiquiatría y neurología. 2) La experiencia de ser un ser consciente no se puede reducir a un programa de software en un robot. 3) La conciencia humana es solo una pequeña región en un vasto espacio de posibles formas de conciencia.
Outlines
💉 La Anestesia y la Conciencia
El orador comparte su experiencia con la anestesia y cómo esta puede causar una sensación de no existencia temporal. Explora la diferencia entre despertar de un sueño profundo y recuperarse de la anestesia, donde la percepción del tiempo puede estar ausente. La anestesia se describe como una 'magia moderna' que transforma a las personas en objetos y luego, esperamos, de vuelta en personas. La conciencia se presenta como uno de los mayores misterios en ciencia y filosofía, y se cuestiona cómo la actividad combinada de miles de millones de neuronas en el cerebro genera una experiencia consciente. El orador sugiere que la conciencia está más relacionada con la naturaleza biológica de los seres vivos que con la inteligencia pura, y que la inteligencia y la conciencia son cosas muy diferentes.
🧠 La Mente como Motor de Predicción
El orador explica cómo la percepción es un proceso de suposición informada en el que el cerebro combina señales sensoriales con expectativas previas para hacer su mejor suposición sobre la causa de esas señales. Se mencionan ejemplos de ilusiones visuales que demuestran cómo el cerebro utiliza expectativas previas para interpretar la realidad, como la ilusión de las manchas de gris que parecen tener diferentes tonos pero son del mismo color. También se presenta un experimento que muestra cómo el cerebro puede cambiar rápidamente lo que percibimos conscientemente basándose en nuevas predicciones. El orador argumenta que la percepción no depende solo de señales entrantes del mundo exterior, sino también, o quizás más, de predicciones perceptivas que fluyen en la dirección opuesta, y que la realidad es una 'alucinación controlada' en la que el cerebro restringe sus predicciones con información sensorial del mundo.
🤲 La Ilusión de la Mano de Gomma y la Experiencia Corporal
El orador discute cómo el cerebro genera la experiencia de tener un cuerpo y cómo este puede ser una especie de 'alucinación controlada'. Se describe el experimento de la 'Ilusión de la Mano de Gomma', donde al tacto y la visión se sincronizan en un objeto que parece una mano, el cerebro asume que es parte del cuerpo. Se sugiere que la experiencia del cuerpo no solo es una cuestión de percepción externa, sino que también incluye la percepción interna de los estados internos del cuerpo, lo que es crucial para la supervivencia. Se menciona otro experimento que combina la realidad virtual con el procesamiento de imágenes para simular la percepción de un brazo en la realidad virtual que parpadea en sincronía con la pulsación del corazón, lo que fortalece la sensación de que es parte del cuerpo. El orador concluye que nuestras experiencias del mundo y de nosotros mismos son formas de alucinaciones controladas que han evolucionado para mantenernos vivos en un mundo lleno de peligros y oportunidades.
🧬 Implicaciones de la Teoría de la Percipción y la Consciencia
El orador expone tres implicaciones de su teoría sobre la percepción y la conciencia. Primero, como podemos malinterpretar el mundo, también podemos malinterpretarnos a nosotros mismos cuando los mecanismos predictivos fallan, lo que abre nuevas oportunidades en psiquiatría y neurología. Segundo, la experiencia de ser un ser consciente no puede reducirse a un programa de software en un robot, ya que las experiencias conscientes están moldeadas por mecanismos biológicos que nos mantienen vivos. Finalmente, nuestra conciencia individual es solo una de las muchas formas posibles de conciencia, y aunque es única para cada uno, está basada en mecanismos compartidos con otras criaturas vivas. El orador celebra estos cambios en nuestra comprensión de nosotros mismos, ya que nos conectan más estrechamente con el resto de la naturaleza y nos permiten apreciar nuestra existencia con menos miedo y más asombro.
Mindmap
Keywords
💡Conciencia
💡Anestesia
💡Neuronas
💡Inteligencia
💡Predicción
💡Ilusiones visuales
💡Realidad
💡Autoexperimento del brazo de goma
💡Intuición corporal
💡Interoceptivo
Highlights
El anestesia es una forma de magia moderna que convierte a las personas en objetos y luego, esperamos, en personas de nuevo.
La conciencia es una de las mayores misterios pendientes en la ciencia y la filosofía.
La conciencia no es solo cualquier experiencia consciente; es tu experiencia consciente aquí y ahora.
La inteligencia y la conciencia son cosas muy diferentes; no tienes que ser inteligente para sufrir, pero probablemente tengas que estar vivo.
Nuestras experiencias conscientes del mundo y de nosotros mismos son tipos de alucinaciones controladas que ocurren gracias a nuestros cuerpos vivos.
La percepción no depende en gran medida de las señales que entran al cerebro, sino de las predicciones perceptivas que fluyen en la dirección opuesta.
No solo percibimos pasivamente el mundo, sino que lo generamos activamente.
La ilusión de la mano de goma muestra que la experiencia del cuerpo también es una especie de alucinación controlada.
Las experiencias de tener un cuerpo están profundamente enraizadas en la percepción de nuestros cuerpos desde dentro.
Nuestras experiencias más básicas de ser un ser encarnado están profundamente enraizadas en los mecanismos biológicos que nos mantienen vivos.
Podemos malinterpretar el mundo y a nosotros mismos cuando los mecanismos de predicción fallan.
Lo que significa ser yo no se puede reducir ni cargar en un programa de software que se ejecute en un robot, sin importar cuán inteligente o sofisticado sea.
Nuestra conciencia y nuestro mundo individual son únicos para cada uno de nosotros, pero están todos enraizados en mecanismos biológicos compartidos con muchas otras criaturas vivas.
Con una mayor comprensión, viene una mayor sensación de asombro y la realización de que somos parte de y no separados del resto de la naturaleza.
Cuando llega el fin de la conciencia, no hay nada de lo que temer.
Transcripts
Just over a year ago,
for the third time in my life, I ceased to exist.
I was having a small operation, and my brain was filling with anesthetic.
I remember a sense of detachment and falling apart
and a coldness.
And then I was back, drowsy and disoriented,
but definitely there.
Now, when you wake from a deep sleep,
you might feel confused about the time or anxious about oversleeping,
but there's always a basic sense of time having passed,
of a continuity between then and now.
Coming round from anesthesia is very different.
I could have been under for five minutes, five hours,
five years or even 50 years.
I simply wasn't there.
It was total oblivion.
Anesthesia -- it's a modern kind of magic.
It turns people into objects,
and then, we hope, back again into people.
And in this process
is one of the greatest remaining mysteries in science and philosophy.
How does consciousness happen?
Somehow, within each of our brains,
the combined activity of many billions of neurons,
each one a tiny biological machine,
is generating a conscious experience.
And not just any conscious experience --
your conscious experience right here and right now.
How does this happen?
Answering this question is so important
because consciousness for each of us is all there is.
Without it there's no world,
there's no self,
there's nothing at all.
And when we suffer, we suffer consciously
whether it's through mental illness or pain.
And if we can experience joy and suffering,
what about other animals?
Might they be conscious, too?
Do they also have a sense of self?
And as computers get faster and smarter,
maybe there will come a point, maybe not too far away,
when my iPhone develops a sense of its own existence.
I actually think the prospects for a conscious AI are pretty remote.
And I think this because my research is telling me
that consciousness has less to do with pure intelligence
and more to do with our nature as living and breathing organisms.
Consciousness and intelligence are very different things.
You don't have to be smart to suffer, but you probably do have to be alive.
In the story I'm going to tell you,
our conscious experiences of the world around us,
and of ourselves within it,
are kinds of controlled hallucinations
that happen with, through and because of our living bodies.
Now, you might have heard that we know nothing
about how the brain and body give rise to consciousness.
Some people even say it's beyond the reach of science altogether.
But in fact,
the last 25 years have seen an explosion of scientific work in this area.
If you come to my lab at the University of Sussex,
you'll find scientists from all different disciplines
and sometimes even philosophers.
All of us together trying to understand how consciousness happens
and what happens when it goes wrong.
And the strategy is very simple.
I'd like you to think about consciousness
in the way that we've come to think about life.
At one time, people thought the property of being alive
could not be explained by physics and chemistry --
that life had to be more than just mechanism.
But people no longer think that.
As biologists got on with the job
of explaining the properties of living systems
in terms of physics and chemistry --
things like metabolism, reproduction, homeostasis --
the basic mystery of what life is started to fade away,
and people didn't propose any more magical solutions,
like a force of life or an élan vital.
So as with life, so with consciousness.
Once we start explaining its properties
in terms of things happening inside brains and bodies,
the apparently insoluble mystery of what consciousness is
should start to fade away.
At least that's the plan.
So let's get started.
What are the properties of consciousness?
What should a science of consciousness try to explain?
Well, for today I'd just like to think of consciousness in two different ways.
There are experiences of the world around us,
full of sights, sounds and smells,
there's multisensory, panoramic, 3D, fully immersive inner movie.
And then there's conscious self.
The specific experience of being you or being me.
The lead character in this inner movie,
and probably the aspect of consciousness we all cling to most tightly.
Let's start with experiences of the world around us,
and with the important idea of the brain as a prediction engine.
Imagine being a brain.
You're locked inside a bony skull,
trying to figure what's out there in the world.
There's no lights inside the skull. There's no sound either.
All you've got to go on is streams of electrical impulses
which are only indirectly related to things in the world,
whatever they may be.
So perception -- figuring out what's there --
has to be a process of informed guesswork
in which the brain combines these sensory signals
with its prior expectations or beliefs about the way the world is
to form its best guess of what caused those signals.
The brain doesn't hear sound or see light.
What we perceive is its best guess of what's out there in the world.
Let me give you a couple of examples of all this.
You might have seen this illusion before,
but I'd like you to think about it in a new way.
If you look at those two patches, A and B,
they should look to you to be very different shades of gray, right?
But they are in fact exactly the same shade.
And I can illustrate this.
If I put up a second version of the image here
and join the two patches with a gray-colored bar,
you can see there's no difference.
It's exactly the same shade of gray.
And if you still don't believe me,
I'll bring the bar across and join them up.
It's a single colored block of gray, there's no difference at all.
This isn't any kind of magic trick.
It's the same shade of gray,
but take it away again, and it looks different.
So what's happening here
is that the brain is using its prior expectations
built deeply into the circuits of the visual cortex
that a cast shadow dims the appearance of a surface,
so that we see B as lighter than it really is.
Here's one more example,
which shows just how quickly the brain can use new predictions
to change what we consciously experience.
Have a listen to this.
(Distorted voice)
Sounded strange, right?
Have a listen again and see if you can get anything.
(Distorted voice)
Still strange.
Now listen to this.
(Recording) Anil Seth: I think Brexit is a really terrible idea.
(Laughter)
Which I do.
So you heard some words there, right?
Now listen to the first sound again. I'm just going to replay it.
(Distorted voice)
Yeah? So you can now hear words there.
Once more for luck.
(Distorted voice)
OK, so what's going on here?
The remarkable thing is the sensory information coming into the brain
hasn't changed at all.
All that's changed is your brain's best guess
of the causes of that sensory information.
And that changes what you consciously hear.
All this puts the brain basis of perception
in a bit of a different light.
Instead of perception depending largely on signals coming into the brain
from the outside world,
it depends as much, if not more,
on perceptual predictions flowing in the opposite direction.
We don't just passively perceive the world,
we actively generate it.
The world we experience comes as much, if not more,
from the inside out
as from the outside in.
Let me give you one more example of perception
as this active, constructive process.
Here we've combined immersive virtual reality with image processing
to simulate the effects of overly strong perceptual predictions
on experience.
In this panoramic video, we've transformed the world --
which is in this case Sussex campus --
into a psychedelic playground.
We've processed the footage using an algorithm based on Google's Deep Dream
to simulate the effects of overly strong perceptual predictions.
In this case, to see dogs.
And you can see this is a very strange thing.
When perceptual predictions are too strong,
as they are here,
the result looks very much like the kinds of hallucinations
people might report in altered states,
or perhaps even in psychosis.
Now, think about this for a minute.
If hallucination is a kind of uncontrolled perception,
then perception right here and right now is also a kind of hallucination,
but a controlled hallucination
in which the brain's predictions are being reined in
by sensory information from the world.
In fact, we're all hallucinating all the time,
including right now.
It's just that when we agree about our hallucinations,
we call that reality.
(Laughter)
Now I'm going to tell you that your experience of being a self,
the specific experience of being you,
is also a controlled hallucination generated by the brain.
This seems a very strange idea, right?
Yes, visual illusions might deceive my eyes,
but how could I be deceived about what it means to be me?
For most of us,
the experience of being a person
is so familiar, so unified and so continuous
that it's difficult not to take it for granted.
But we shouldn't take it for granted.
There are in fact many different ways we experience being a self.
There's the experience of having a body
and of being a body.
There are experiences of perceiving the world
from a first person point of view.
There are experiences of intending to do things
and of being the cause of things that happen in the world.
And there are experiences
of being a continuous and distinctive person over time,
built from a rich set of memories and social interactions.
Many experiments show,
and psychiatrists and neurologists know very well,
that these different ways in which we experience being a self
can all come apart.
What this means is the basic background experience
of being a unified self is a rather fragile construction of the brain.
Another experience, which just like all others,
requires explanation.
So let's return to the bodily self.
How does the brain generate the experience of being a body
and of having a body?
Well, just the same principles apply.
The brain makes its best guess
about what is and what is not part of its body.
And there's a beautiful experiment in neuroscience to illustrate this.
And unlike most neuroscience experiments,
this is one you can do at home.
All you need is one of these.
(Laughter)
And a couple of paintbrushes.
In the rubber hand illusion,
a person's real hand is hidden from view,
and that fake rubber hand is placed in front of them.
Then both hands are simultaneously stroked with a paintbrush
while the person stares at the fake hand.
Now, for most people, after a while,
this leads to the very uncanny sensation
that the fake hand is in fact part of their body.
And the idea is that the congruence between seeing touch and feeling touch
on an object that looks like hand and is roughly where a hand should be,
is enough evidence for the brain to make its best guess
that the fake hand is in fact part of the body.
(Laughter)
So you can measure all kinds of clever things.
You can measure skin conductance and startle responses,
but there's no need.
It's clear the guy in blue has assimilated the fake hand.
This means that even experiences of what our body is
is a kind of best guessing --
a kind of controlled hallucination by the brain.
There's one more thing.
We don't just experience our bodies as objects in the world from the outside,
we also experience them from within.
We all experience the sense of being a body from the inside.
And sensory signals coming from the inside of the body
are continually telling the brain about the state of the internal organs,
how the heart is doing, what the blood pressure is like,
lots of things.
This kind of perception, which we call interoception,
is rather overlooked.
But it's critically important
because perception and regulation of the internal state of the body --
well, that's what keeps us alive.
Here's another version of the rubber hand illusion.
This is from our lab at Sussex.
And here, people see a virtual reality version of their hand,
which flashes red and back
either in time or out of time with their heartbeat.
And when it's flashing in time with their heartbeat,
people have a stronger sense that it's in fact part of their body.
So experiences of having a body are deeply grounded
in perceiving our bodies from within.
There's one last thing I want to draw your attention to,
which is that experiences of the body from the inside are very different
from experiences of the world around us.
When I look around me, the world seems full of objects --
tables, chairs, rubber hands,
people, you lot --
even my own body in the world,
I can perceive it as an object from the outside.
But my experiences of the body from within,
they're not like that at all.
I don't perceive my kidneys here,
my liver here,
my spleen ...
I don't know where my spleen is,
but it's somewhere.
I don't perceive my insides as objects.
In fact, I don't experience them much at all unless they go wrong.
And this is important, I think.
Perception of the internal state of the body
isn't about figuring out what's there,
it's about control and regulation --
keeping the physiological variables within the tight bounds
that are compatible with survival.
When the brain uses predictions to figure out what's there,
we perceive objects as the causes of sensations.
When the brain uses predictions to control and regulate things,
we experience how well or how badly that control is going.
So our most basic experiences of being a self,
of being an embodied organism,
are deeply grounded in the biological mechanisms that keep us alive.
And when we follow this idea all the way through,
we can start to see that all of our conscious experiences,
since they all depend on the same mechanisms of predictive perception,
all stem from this basic drive to stay alive.
We experience the world and ourselves
with, through and because of our living bodies.
Let me bring things together step-by-step.
What we consciously see depends
on the brain's best guess of what's out there.
Our experienced world comes from the inside out,
not just the outside in.
The rubber hand illusion shows that this applies to our experiences
of what is and what is not our body.
And these self-related predictions depend critically on sensory signals
coming from deep inside the body.
And finally,
experiences of being an embodied self are more about control and regulation
than figuring out what's there.
So our experiences of the world around us and ourselves within it --
well, they're kinds of controlled hallucinations
that have been shaped over millions of years of evolution
to keep us alive in worlds full of danger and opportunity.
We predict ourselves into existence.
Now, I leave you with three implications of all this.
First, just as we can misperceive the world,
we can misperceive ourselves
when the mechanisms of prediction go wrong.
Understanding this opens many new opportunities in psychiatry and neurology,
because we can finally get at the mechanisms
rather than just treating the symptoms
in conditions like depression and schizophrenia.
Second:
what it means to be me cannot be reduced to or uploaded to
a software program running on a robot,
however smart or sophisticated.
We are biological, flesh-and-blood animals
whose conscious experiences are shaped at all levels
by the biological mechanisms that keep us alive.
Just making computers smarter is not going to make them sentient.
Finally,
our own individual inner universe,
our way of being conscious,
is just one possible way of being conscious.
And even human consciousness generally --
it's just a tiny region in a vast space of possible consciousnesses.
Our individual self and worlds are unique to each of us,
but they're all grounded in biological mechanisms
shared with many other living creatures.
Now, these are fundamental changes
in how we understand ourselves,
but I think they should be celebrated,
because as so often in science, from Copernicus --
we're not at the center of the universe --
to Darwin --
we're related to all other creatures --
to the present day.
With a greater sense of understanding
comes a greater sense of wonder,
and a greater realization
that we are part of and not apart from the rest of nature.
And ...
when the end of consciousness comes,
there's nothing to be afraid of.
Nothing at all.
Thank you.
(Applause)
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