Exploring the nature of perception, and how this might impact on
Cobb: 'They say we are only
using a fraction of our brain's true potential. That's when we are
awake. When we are asleep, our mind can do almost anything'
Ariadne: 'Such as?'
Cobb: 'Imagine you are
designing a building. You consciously create each aspect. But
sometimes it feels like it is creating itself.'
inspiration, right. Now, In a dream, our mind continuously does
this: we create and perceive our world simultaneously. Our mind does
this so well we don't even know it is happening. This allows us to
get right in the middle of that process by taking over the creative
from a conversation between the characters Cobb (played by Leonardo
di Caprio) and Ariadne (played by Ellen Page) in the film Inception
Consider the following common expressions:
These all reflect the fact that it's not
uncommon for two people people to share their version of an
experience in very different ways. Is this because of their poor
recall of events? Or is it that they actually experienced something
Is what we see what is really there?
Skilled illusionists are able to trick us remarkably consistently
they have an innate understanding of how the human visual system
works, and take advantage of this. We're amazed by what they do,
because we trust our eyes.
Visual illusions and there are many
of them show us clearly that we don't always see what is
actually there. If our visual systems are constructing a view of
reality complete with flaws, then this poses a crucial question: how
much of our experience of reality is actually real?
I suspect that my experience of the world
is very different from the way my dog experiences the world. When we
take a walk together, if she were able to speak, her account of the
reality that we shared on the walk would be very different from
mine. My experience is very visually dominated. Hers seems to be
dominated by smell. As she stops and sniffs, she detects signals
that are hidden from me. She leaves her own signals. When she meets
another dog, a large part of the interaction takes place through
mutual smelling. It's a world largely closed to humans.
The assumption here, of course, is there
is a reality out there, that we have in common: an external
environment in which we live and move and breath. How we experience
this reality depends on the particular sensory apparatus we have and
crucially how the we use our brain processing to interpret
this sensory input and assemble it into a conscious experience.
Rodents have an important sensory system
involving a specialized form of touch: their whiskers are part of a
vibrissal system that allows them to map the world spatially even in
the dark. Bats use ultrasound to navigate. All these sensory systems
are creating a slightly different account of the same reality - the
external world. Yet we are so used to our own particular account of
the world that our unspoken assumption is that how we perceive it is
the way that it is.
Of course, it makes sense in practical
terms to make this assumption, because our sensory systems and the
processing of these signals allows us to model reality in a way that
extracts out the information useful to us for our decision making.
But our perception is, by necessity, partial. More importantly, I
will argue that what we perceive is not necessarily what is there.
'Reality', as we perceive it, is something unique to each of us. To
is a unity
Sensation is a unity. We are used to
thinking of senses as discrete entities: sight, smell, taste, touch,
sound. But our experience of the world is a single, unified
perception. At the moment I'm receiving lots of information from the
outside world, and also from my own internal state. But unless I
specifically attend to various elements of this information, I'm not
really aware of most of it. As long as I don't feel hot or cold, I'm
not thinking about the air temperature. As long as I don't have a
sore back, or have been sitting in the same position for too long,
for example, I'm not aware of touch.
I concentrate on my laptop, unaware of
all the information in my peripheral vision, save for motion, which
seems to pop out. If someone moves particularly fast, or comes very
close to me, I can easily ignore it. There's a hum of background
noise: I will only be aware of this when something alerts me, and
then my stereo vision will guide my eyes to look in the direction of
where the loud or unusual sound has come from.
By the time we are aware of the
environment around us, a lot of processing has already taken place
to the sensory information we have picked up. It is as if our
perception is akin to the chief executive
of a large company who doesn't want to know all the little
details, but just what is important in helping her make critical
decisions. She receives an edited version of what takes place in the
company with the uneccessary material taken out. This is the only
way she can work effectively.
This higher-order processing by the brain
fuses together sensory input from a variety of sources, adds into
the mix our own internal state, and then delivers to our
consciousness a model of the world out there that is relevant to us,
with the largely irrelevant details relegated to the background.
With vision, this processing is clear. We have specialized modules
for face processing, for example. In our field of view, faces are
very important. So part of our visual processing is involved in
recognizing faces from a scene and affording them special
significance. Likewise, our peripheral vision is very sensitive to
motion, because moving objects just out of our main field of view
are likely to be important.
Colour is interesting. Let's take just
one colour: red. The colour 'red' does not exist in nature. It is
entirely subjective. This can be shown by context effects, where a
'red' shape can be placed in the context of surrounding colours that
cause it to be perceived differently. Looking at it the other way
round, 'red' is normally experienced when our photoreceptors are hit
by light of a certain wavelength. But context experiments show that
the brain then processes this information such that in some
instances red isn't red at all, demonstrating that redness is
something that we construct.
Another interesting observation is the
response of captive-bred infant monkeys to a plastic snake. As you'd
expect, they have no fear of snakes. But they develop fear of snakes
if they are shown a film of a monkey showing a fear response to a
toy snake. If the film is changed so that the fear response is to
another object, say a flower, then the captive-reared monkeys don't
develop a fear of flowers. So it is as if there is something innate
in monkeys that prepares them to learn to fear snakes. Even though
these infant monkeys have never seen a snake, they have an innate
emotional response to the visual stimulus of seeing a lifelike model
snake once they have seen another monkey react fearfully to that
snake. This means that hard-wired in their brains is some processing
that attributes significance to a snake-like object. Pigeons have a
similar response to the shadow of a hawk one that seems hard
Where am I going with all this? I am
trying to make a case for the subjective nature of our perception of
the world around us. Our perception, which is a unity, is based on a
common shared reality of what is out there. But it also includes
important components that come from us. We model reality. By the
time we are aware of what is out there, we are experiencing
something that is, to a degree, unique to us. We are, in effect,
This line of argument seems a little
dangerous. It sounds strongly relativist. But it is not to dismiss
all objectivity, and it does not mean that anything goes. For all
intents and purposes, our notion of the world around us is largely
an accurate one, but it is not as accurate as we would like to
In order for us to respond rapidly to a
changing and sometimes surprising environment, it seems that we have
had to do a fair amount of interpreting and modelling of what is out
there before we are consciously aware of it. We take sensory
information about the environment around us, but we don't have time
or processing power to take all of it and process it accurately, so
instead we focus on those elements that are most likely to be of use
to us, and use these to model reality.
The fact that this extracted information
is then subjected to interpretation is of great interest to me. This
could be the reason that different people have such different
experiences of the same events. Their experience of reality is
subtly but significantly different, because of the way they
interpret it even before they are aware of it.
This all suggests that the brain has some
way of generating 'reality' from relatively limited external input.
And could it be that the mechanism for generating 'reality' could
even function in the absence of external input?
This is where dreams come in. I've always
been intrigued by my dreams. The experiences I have as I dreams
sometimes seem incredibly real. Yet they are not simply based on
experiences I have had. They involve situations that are entirely
novel. Yes, sometimes I can see a link between recent experience and
the content of my dreams. But often there is no such connection, and
the ideas and experiences I have in my dreaming state are often
Dreams could be an artefact of the
brain's reality-generating module. I would go further, and say that
they represent evidence of what the brain is doing in our perception
of reality. The cues received from our senses kick into action this
reality-generating module which then creates our perception. Thus
perception itself could be internally generated, albeit based on an
external reality. This seems quite a scary thought, but it fits well
with the reality of perception.
Further evidence for this reality
generation come from the effects of psychotropic substances.
Hallucinating hippies, high on drugs, experience a starkly different
'reality' to the rest of us. Could it be that the ability of some
chemicals to induce hallucinations is because they tap into the
brain's reality-generating module, with surprising results?
Why would the brain have the ability to
create reality if this were not a useful or important feature? It is
unlikely to be a side-effect of some other functional process. And
it is hard to imagine how a psychotropic drug might create reality
unless it is tapping into some pre-existing module or mechanism
designed for this purpose.
So what are the implications of this for
wine? There is no reason not to think that our perception of flavour
is something we generate, based on the physical properties of the
food or drink we are consuming. These physical properties include
chemistry, but also importantly the appearance of the
food/drink. We bring a good deal to the encounter, too. Our
experience, knowledge and expectations, as well as our internal
state, will shape our perception.
Perception of flavour isnt just about
taste and smell. Our perception is a unity, and flavour is a part of
that unity. Its more than just multimodal (that is, it involves
several senses) part of flavour perception is internally
generated. In this sense, flavour is not a property of the wine we
This is something we need to bear in mind
in the way that we discuss wine, the way we carry out tastings, and
also the way that we communicate about wine. It doesn't mean that
wine is totally subjective after all, there is a surprising
amount of agreement when we taste wine together. But it calls for an
enriched, more grown-up understanding of the nature of wine tasting
than the current model that is taught to students of wine.
philosophy of wine
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