Topics

   
1.	The chief goals of this work have been to describe haptics,
how the world can be represented, and the roles of the
physical vantage point of the observer, and the observer's
intention.  In short, the work deals with haptics,
representation, observers and purposes.   Can the blind
capitalize on these?  Arnheim, for example, notes it is a
far cry from being an observer at a fixed location to the
ability to draw in perspective.  Arnheim, following Kant,
notes we are "rational animals" Ð our rationality is the base
for our ability to notice errors, and to discern some are
intentional and could be metaphors.

2.	Arnheim, describing touch, takes it to be "dynamic" and
concerned with "pushes and pulls" Ð which at best might
yield abstract and shapeless impressions.  Contrary to this,
I argue haptics is concerned with resistance, and gets
impressions of shape from variations in resistance as well
as dynamic impressions of force, effort, pushes and pulls.

3.	The most notable precursor to the present position is Denis
Diderot (late 1700s) who averred:

a.	touch excels at 3ÐD exploration
b.	touch involves interposition in 3ÐD (and hence
aspects of perspective)
c.	touch uses acts across time
d.	touch integrates across time
e.	touch's information can be used in mental imagery, at
a range of scales, including the scale of the whole
world
f.	touch can use LINES DRAWN ON THE HAND AS
DEPICTIONS!

4.	Diderot's notes about drawing on the hand are
prescient about electronic devices making shapes on the
finger pad e.g. the OPTACON (which makes a pattern on
a finger pad) and the TVSS (television sensory substitution
device). The TVSS is an enlarged version of the Optacon,
including a camera to focus on distant objects, and
displays which are applied to a large area of skin e.g. the
back.  These devices are quite hard to use.  It may be the
skin normally provides information to guide the motion of
the joints, and shape information in tactile perception
comes from the joints. Finger pads and large areas of skin
do not yield clear impressions of shape, in this account.

5.	Diderot lacked a theory of pictures, e.g. a theory of
the features for which outlining is suitable.  His theory of
perception was illogical:  Meaningless sensations are
turned into meaningful percepts of objects, he suggested,
by comparing the sensations with the objects which caused
them.  This theory assumes the observer has independent
knowledge of the objects!  But all the observer has actually
is the "sensations".  Diderot does not explain how the
independent knowledge could arise.



6.	If we claim sensations are meaningless, how can we
get meaning back, to produce "meaningful percepts"? 
Surely the answer lies in denying that the observer has
meaningless sensations.  Rather, the observer has a rich
base of information, full of useful detail.  Also, the basic
elements Ð contour and line, for example Ð act as
"meaningful" surrogates for a limited set of powerful
spatial features (features that could describe much of the
world i.e. edges of surfaces).

7.	The key surrogate function is that contours and lines
show RELIEF by acting as single AXES that are
independent of BRIGHTNESS (figure 9.1).  Since axes
are independent of brightness, and show relief, they could
be relevant to touch.  This implication has borne out (see
figure 9.2) in several ways.  Relief is always perceived
from a vantage point Ð which has implications for
perspective (see figure 9.3 Ð a blind person's drawing of
railroad tracks).

8.	Let us review the key steps in the argument.

9.	Chapter 1.  Is touch proximal only?  No, it is distal too.  That is, touch "gets relief": It gets surfaces, and hence
occlusion, corners and vantage points. 
Hence it detects objects, and scenes, uses media between
objects, all of which take time to explore.			 
     These principles are comparable to those in vision, as far
as direction and distance are concerned.  In brief Ð touch
does respond to energy and dynamism and resistance? 
Yes.  But pattern and space too! 

Hence, representational patterns could be apt for touch,
and errors in representation could be detected, and give
information about intentions.

Are there limits to touch?  Yes.  Touch takes lots of time, 
often (but vision takes some time, of course).  Skilled
touch does need to be better understood.

10.	Chapter 2:  What can outline show?  The visual
functions of line in depiction include showing edges of
surfaces Ð features that are tangible. But outline is not
successful with shape Ð from Ðshadow boundaries or
forms.  Lines (with two contours) show a single edge, by
means of a single axis.  The axis is perhaps "amodal"  (not
dependent on modal properties like brightness or colour). 
Our contemporary theory of vision's physiology is a thing
of shreds and patches, and is unable to explain "axes" and
related phenomena as yet.

11.	Chapter 3:  Do the implications of chapters One and
Two hold up?  Can the blind in fact recognize outline
pictures?  Their exploration is slow and laborious, but they
do manage to recognize some pictures unaided, on first
exposure.  With some support, success rates in the 40Ð
60% range are often possible.  Higher rates can be attained
at times with modest support and brief practice.  
Could high rates be attained reliably and widely? 
Probably.

12.	Chapter 4:  Can blind people draw, using outline? 
Yes, often somewhat recognizably and at times quite well. 
Further, occasionally vantage points are explicitly noted. 
Familiar complex objects such as dogs are difficult for the
blind Ð but they are for the sighted too.  And at least one
person can draw such objects quite competently.

Limits?  There are three factors to reconcile Ð the vantage
point, the object and the orientation of the picture plane. 
The third factorÐ the picture plane's orientation Ð is not
entertained systematically (but this is a problem for the
sighted too).  Also, dogs and like animals involve
systematic variation along the length of their borders Ð this
is hard to draw.  If the proportions of the drawing are off,
slightly, the species is unclear, or an object that is no
particular animal is evident.  (This final point needs more
careful analysis in the future).

13.	Chapter 5: 1s drawing development similar in the
blind and the sighted?  Yes, they have many hallmarks in
common:  Initial will to represent; use of a spatial
dimension and features of shape; a single complete facet of
a form (e.g. a face of a square); connected facets (foldout);
use of a vantage point to select facets; some use of
foreshortening; occasional, rare use of convergence.  Also,
what were initially shape variations caused by miming a
motion may be evident later as deliberate metaphoric
variations on a shape.

Limits?  No longitudinal study of drawing development
has been done.  That is a task for the future.

14.	Chapter 6:  Vantage points and aspects of perspective
Ð are they used by the blind?  The blind mention these,
spontaneously.  They judge drawings using aspects of
perspective to be developmentallyÐolder than foldout
drawings.  They can match drawings of different objects
that use the same perspective systems.

Limits?  The blind do not show any hints of a clear grasp
of the ways to scale and measure the amount of
convergence that is required, as the orientation of the
picture changes Ð but this is rather like problems evident in
the sighted.

15.	Chapter 7: Can error be metaphoric in pictures?  Yes,
key features can be emphasized, by putting them where
they do not belong.  These key features have to be apt or
relevant.  These violations of nature are not done to alter
our understanding of the locations of the features, unlike a
presentation of a new theory or proposal.  Rather, they are
put in unrealistic places merely to bring these features of
the referent to mind.  The blind and the sighted recognize
a wide variety of metaphoric devices e.g. motion, pain etc.

16.	Chapter 8:  Universals that are not conventions
include elements in pictures giving rise to impressions Ð
notably figure Ð ground or relief edges.  These affect
recognition in the sighted.  Similar recognition effects
have been found for the blind.  Impressions are
occasionally described by the blind.  The use of two
elements (contours) to depict one feature (an edge), by
means of one axis, may have a parallel in responses to
vibrations  by hearing and touch. Two tones an octave
apart have a special relation in touch as well as in hearing. 
The convention thesis has no account of the powers of
elements such as lines and contours.  Elements can make
simple forms with abstract referents (e.g. marriage) or
relations between people (stick figures) and possibly, can
support apt art styles with abstract uses (e.g. cubism).

We have no clear, organized set of "perceptual
experiences" or "abstract referents" to be a guide or map of
possible topics for research into universals.  But the fact
that pain can be depicted by the same devices for the blind
and the sighted suggests we can show the two groups feel
private experiences like pain in the same way.

17.	Overall:  Lines give experiences, and make up
shapes.  Shapes are governed by the world's physical
geometries.  Thinking depends on features, including
features of shape, and classÐinclusion mechanisms using
these features.  We can represent features realistically or
quite intentionally we can represent the features
unrealistically.  Intention governs expression
(representation).

The blind share these fundamental aspects of our
psychology.  In studying experiments comparing the blind

and the sighted we discover much about how all people
think,  will, represent and experience a common world.
Q.E.D.  

Thank you for your kind attention.	







Scarborough College

Table of Contents

Figure 7.1





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