And it is found that, in these cases, what we see depends very much on what we wish to see.

The interpretation adopted is still, in a sense, the result of suggestion, but of one particular suggestion which the fancy of the moment determines.

Or, to put it another way, the caprice of the moment causes the attention to focus itself in a particular manner, to direct itself specially to certain aspects and relations of objects.
The eye's interpretation of movement, already referred to, obviously offers a wide field for this play of selective imagination.

When looking out of the window of a railway carriage, I can at will picture to my mind the trees and telegraph posts as moving objects.

Sometimes the true interpretation is so uncertain that the least inclination to view the phenomenon in one way determines the result.