Let us now glance at the results of definite preimagination, including what are generally known as expectations.
_Effects of Vivid Expectation._ Such expectations may grow out of some present objective facts, which serve as signs of the expected event; or they may arise by way of verbal suggestion; or, finally, they may be due to internal spontaneous imagination.
In the first place, then, the expectations may grow out of previous perceptions, while, nevertheless, the direction of the expectation may be a wrong one.

Here the interpreting imagination is, in a large sense, under the control of external suggestion, though, with respect to the particular impression that is misconstrued, it may be regarded as acting independently and spontaneously.
Illustrations of this effect in producing illusion will easily occur to the reader.

If I happen to have heard that a particular person has been a soldier or clergyman, I tend to see the marks of the class in this person, and sometimes find that this process of recognition is altogether illusory.

Again, let us suppose that a person is expecting a friend by a particular train.

A passenger steps out of the train bearing a superficial resemblance to his friend; in consequence of which he falls into the error of false identification.
The delusions of the conjuror depend on a similar principle.