Varieties of perception 47
camp of ecological psychology. It says that the Gibsonian conception of information “is roughly the claim that real possibilities are specified by current states of
affairs” (Turvey et al. 1981, 293). On this view (which is largely shared here), the
requisite information is present only if the affordance or “possibility” in question
is real, and hence is warranted by current states of affairs. Sometimes, the perceiving organism will have to find out the hard way whether a possibility is real, and
whether the information he seemed to pick up is there at all. Quite often, however, he has means of reliably making that distinction in the course of perceptual
activity.
There is a variety of ways of being mistaken about some world affair, which are
only partly acknowledged by Gibson. In his Ecological Approach, he only briefly
and tangentially refers to misperception and perceptual illusions, and he does so
primarily in the context of artfully created illusions. His prime examples are of
two kinds:
(pi 1) Pictures that are purposefully made to create the appearance of objects
that are not present in the environment.
(Gibson 1979, 281–283)
It is quite remarkable to hence find pictures subsumed under illusions, but this
claim is consistent with Gibson’s theory, and its normative connotations are not
negative by default. A picture of some concrete object will contain some of the
information that would be necessary for the object in question to provide the requisite affordance in its proper environment to its perceiver, yet without actually
providing that affordance – for example sitting-on and sitting-at for the picture
of a chair and a table. In such cases, we normally recognise both that would-be
affordance and the pictorial nature of what is presented to us, and hence are not
misguided. We are able to do so primarily because we actively explore what we
perceive, by moving our eyes and heads in relation to an object. Only if and when
we did not hence “test for the reality” of what we perceive, there could be such a
thing as a perfect picture that tricked us into mistaking it for the scene that is being
pictured (Gibson 1970, 426):
4
(pi 2) Devices that are purposefully placed in the environment so as to create
discontinuities in perception.
Drawing on the experimental work of his wife, Eleanor J. Gibson (Gibson
and Walk 1960), Gibson cites as the paradigm of such artfully created illusions planes of solid glass that extend over visual cliffs and thus provide support while maintaining the visually based affordance of falling off the cliff
(Gibson 1979, 142f ). Here, conditions are modified in such a way as to create
a mismatch between current states of affairs and an affordance or “possibility”,
which thus becomes “unreal”. Misguiding the subject’s perception is one central aim of the experiment, so the purpose of the artefact is clearly at variance
with (pi 1).
camp of ecological psychology. It says that the Gibsonian conception of information “is roughly the claim that real possibilities are specified by current states of
affairs” (Turvey et al. 1981, 293). On this view (which is largely shared here), the
requisite information is present only if the affordance or “possibility” in question
is real, and hence is warranted by current states of affairs. Sometimes, the perceiving organism will have to find out the hard way whether a possibility is real, and
whether the information he seemed to pick up is there at all. Quite often, however, he has means of reliably making that distinction in the course of perceptual
activity.
There is a variety of ways of being mistaken about some world affair, which are
only partly acknowledged by Gibson. In his Ecological Approach, he only briefly
and tangentially refers to misperception and perceptual illusions, and he does so
primarily in the context of artfully created illusions. His prime examples are of
two kinds:
(pi 1) Pictures that are purposefully made to create the appearance of objects
that are not present in the environment.
(Gibson 1979, 281–283)
It is quite remarkable to hence find pictures subsumed under illusions, but this
claim is consistent with Gibson’s theory, and its normative connotations are not
negative by default. A picture of some concrete object will contain some of the
information that would be necessary for the object in question to provide the requisite affordance in its proper environment to its perceiver, yet without actually
providing that affordance – for example sitting-on and sitting-at for the picture
of a chair and a table. In such cases, we normally recognise both that would-be
affordance and the pictorial nature of what is presented to us, and hence are not
misguided. We are able to do so primarily because we actively explore what we
perceive, by moving our eyes and heads in relation to an object. Only if and when
we did not hence “test for the reality” of what we perceive, there could be such a
thing as a perfect picture that tricked us into mistaking it for the scene that is being
pictured (Gibson 1970, 426):
4
(pi 2) Devices that are purposefully placed in the environment so as to create
discontinuities in perception.
Drawing on the experimental work of his wife, Eleanor J. Gibson (Gibson
and Walk 1960), Gibson cites as the paradigm of such artfully created illusions planes of solid glass that extend over visual cliffs and thus provide support while maintaining the visually based affordance of falling off the cliff
(Gibson 1979, 142f ). Here, conditions are modified in such a way as to create
a mismatch between current states of affairs and an affordance or “possibility”,
which thus becomes “unreal”. Misguiding the subject’s perception is one central aim of the experiment, so the purpose of the artefact is clearly at variance
with (pi 1).