[extropy-chat] Questionnaire on senses

Anders Sandberg asa at nada.kth.se
Sat Jan 27 15:33:47 UTC 2007

ben wrote:
> Anders wrote:
>  >I wonder if odors could be used in ambient information visualisation
>  >(odification?). Imagine having the relative development of your stocks
>  >waft through the ventilation as a discreet odor mix.
> I had to read that twice, thought you were talking about socks, not
> stocks.
> Which would make more sense to me!

Hmm, maybe one could have clothing that actually provided olfactorisations
of data. Right now there is a natural data in the form of the smell of
bacterial flora interacting with past body states, which is certainly a
complex olfactorisation but hardly anything most people care about (one
day I'm going to get myself some petri dishes and start to identify
exactly what species make what smells, just for fun).  Given that we both
have bactericidal clothing being developed and people are doing
visualisation clothing I think one could combine this.

> And i'm not sure why, if smells have
> visual equivalents, you wouldn't just use the visual data in the first
> place? Probably much easier to encode digitally, for one thing, as well
> as more accessible to people.

A real olfactorisation would not induce a visual image but rather a sense
of smell context. Imagine that processor usage is denoted by spicy smells,
hard drive usage by earthy smells, memory usage by bakery smells,graphics
card usage by flowery smells and detected errors by some more stinking
smells. When I start my big mathematical calculation I will get a rough
context of an exotic bakery (CPU, memory). After a while the smells start
to drift towards the earthy as results start to get written onto the
harddrive (maybe a rather rustic bakery). Suddenly I notice a stink: there
is a HD fault. Swapping the drive I get back to the sense of bakery, which
now appears to move into the garden as the visualisation software starts.
If there were a new fault, I might get the sense of a bit of rotten fruit
(putrid + flowery).

> Is sandalwood higher or lower than acetone? :)

Acetone is a very pure, high slightly wavery line. It is one of the few
smells I tend to "see" in the left visual field rather than the right. In
most cases "high" smells are more volatile than "low" smells. It is very
much like taste: first you experience the volatile substances, then the
water soluble ones and finally the fat soluble and high molecular weight

> I agree with statements that the visual sense tends to be
> the highest bandwidth (most bits/s).  But there are only 3 receptors --
> everything else is subjective interpretation (as color blind or color
> variant people are able to discuss).  On the other hand sound and smell
> would seem to offer much more refined senses.  In sound I believe that the
> location of the perception is allowing different frequency differentiation
> while in smell one is dealing with different types of receptors, their
> quantity, location, etc.  I would tend to relate sound to overall "touch"
> sensation.  Its "where" the stimulation is perceived that counts.

Yes, auditory processing has affordances for very subtle location
determination just from sound (humans can do a bit of echolocation). It is
pretty amazing that we can sense that sounds come from straight above!
There is a pretty impressive system in the parietal lobe meshing visual,
auditory and somatosensory signals into a world model so that they appear
to come from locations in an allocentric rather than an egocentric
coordinate system.

Still, location is just one form of data.

>But in terms of overall variety, in humans, it has to be sight < taste <
>hearing < smell < touch.  Touch wins out on the basis of larger surface
>area and mutiple sensors (heat, pain, pressure, etc.).

But that is just bandwidth. if you look at cortical processing area vision
wins out - we do much more with that than with touch.

The thing smell can do that no other sense can is to directly interact
with the limbic system (OK, there is a side-pathway via the pulvinar in
the visual system that goes to the amygdala, relevant to people with
phobias). Smells can rather directly evoke memories and emotions. They get
directly integrated in a general context in the hippocampal system rather
than treated as elements to be analysed and then put together.

Anders Sandberg,
Oxford Uehiro Centre for Practical Ethics
Philosophy Faculty of Oxford University

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