Martin Taylor [2010.04.29.16.05]
[From Rick Marken (2010.04.28.1520)]
Martin Taylor
(2010.04.28.15.52)
Rick Marken (2010.04.27.0910)]
I think the concept of “affordance” – the
idea that pattern
recognition can detect aspects of things that can tell the behaving
system (inform it about) how to use them –
I’m surprised you got this notion of “environmental affordance” from my
writing. It seems to derive more from the Gibsonian idea of perceptual
affordances than from the concept I’ve been trying to get across.
I know that your concept of affordance is different than Gibson’s. I
was responding to Bruce Gregory, whose concept of affordance (along,
apparently, with Hawkins’) is precisely Gibson’s. To prevent confusion
I would suggest that you use a different name for the concept you’ve
been calling affordance. I would suggest that you call what you are
talking about “environmental degrees of freedom”.
It has nothing to do with environmental degrees of freedom, except that
if the degrees of freedom are zero, there is no environmental
affordance.
These are the characteristics of the environmental feedback path
that either allow or inhibit control (as in my “Cost of Conflict” demo
at http://www.mindreadings.com/ControlDemo/Conflict.html,
where, when the degrees of freedom in the environment are reduced from
2 to 1 it is impossible to control the cursor in two dimensions).
This is true but irrelevant.
Separately [From Rick Marken (2010.04.29.0830)], you said: "
So for Martin, the connection between the mouse and the cursor in a
tracking
task is an “affordance” which makes control possible (if the
connection exists) or impossible (if it’s broken). But the connection
itself cannot be perceived,…."
The first part of this is correct, but the second may or may not be
correct in any particular case. The connection is as perceptible as is
any relationship. The influence of the output on the perception is a
relationship, but the relationship[ is not itself an environmental
affordance. The connection as an affordance is at a different level of
perception (typically a program perception), which, to repeat myself
from earlier messages, may be characterized: “If I move the mouse left,
the cursor will move left.” Someone new to computers would not be
expected to start with any perception of that affordance, but some
experimentation with the device is likely to allow the person to
generate it, in much the same way as one develops the perception that
if one sees the clouds thickening and darkening, it is likely to rain
soon (which is not an environmental affordance in itself, but which
could contribute to one).
Continuing, you said: “I presume it would be an “affordance” for you or
Hawkins because you can’t tell, by looking at the mouse or computer,
whether the mouse “affords” control over the cursor.”
Simply by looking at the mouse or computer, you can’t tell, as my
comment about the computer-naive person suggests. But if you are
familiar with computers that allow mouse control of the cursoe, and can
see that the mouse is connected to that particular computer, then you
can perceive the affordance. But the environmental affordance is there
whether you perceive it or not, which is why I queries a few messages
ago how to distinguish the affordances that exist (such as Rick’s
jailbreak) from those that are perceived.
Since we are getting into issues of the reality of the external world,
I think it is probably better to take the perception as the default
case, and use special language to deal with environmental affordances
perceived only by an external observer/analyst. The problem is that, to
take an extreme example, a jet plane was a possible way of crossing the
Atlantic in 1750, but nobody had perceived the possibility, or of the
steps needed to make it plausibility. It was, theoretically, an
environmental affordance for someone wanting to cross the ocean, but it
was not a practical one, whereas now it is a practical affordance.
There’s no clear sharp boundary between environmental affordances such
as that of the jet plane in 1750 (obviously impractical) and the plank
that could be placed across the stream (an obviously practical
environmental affordance). The only sharp boundary is perceptual. Those
that are perceived are the ones that could be used if some controlled
perception might use the corresponding environmental feedback path.
Those that are not perceived (or that have not been embodied in
evolution or reorganization) cannot be used.
Martin
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