It may seem that these data 
finally can give us an answer to 
Stratton’s question. The image 
need not be inverted for upright 
vision to occur; it can be 
oriented in a different way 
than it ordinarily is. There is, 
however, an important reason 
why this conclusion may be 
incorrect. Is adaptation to a 
tilted image egocentric? 
Suppose, as in Stratton’s 
experiment, the visually 
altered scene, over time, begins 
to look like one that is 
environmentally upright--that 
is, not tilted with respect to the 
direction of gravity. Suppose, 
further, that this is the only 
kind of adaptation that occurs. 
Because the image is tilted 30 
degrees on the retina, 
observers would have to 
experience themselves or just 
their heads as tilted for that 
image to represent a vertical 
line in the environment. The 
kind of adaptation that is 
occurring thus may be an 
adaptation to the direction of 
the scene in relation to gravity, 
but not in relation to the self. 
In the latter instance, there 
may be no egocentric change, 
just as may have been the case 
in Stratton’s experiment. But 
the evidence on this question 
is not yet sufficient to resolve 
it.

While the two kinds of 
orientation perception have 
been discussed separately in 
this chapter to avoid confusion 
of issues, the fact is, of course, 
that they are both 
simultaneously occurring 
aspects of perception in daily 
life as well as in the 
experiments described. For 
example, when upright 
observers enter a tilted room 
and tend to perceive the room 
as upright, they necessarily 
must perceive themselves as 
tilted. What was not made 
explicit earlier in the 
discussion of this experiment 
is that they perceive 
themselves as tilted because 
they immediately detect that 
they are not aligned with the 
room--that is, they perceive 
that they are tilted with respect 
to it. This is based on 
perceiving the egocentric 
orientation of the room. Since 
its image is tilted on the retina, 
it appears tilted from the main 
axis of the body. Integrating all 
this information, the 
perceptual system arrives at the 
overall "solution": room 
upright, body tilted from 
upright. The two aspects of the 
perception of orientation, 
therefore, work hand in hand.