Oedipus effect

The Oedipus effect is where the prediction of an event influences the occurence of that event (whether it increases the likelihood of that event or decreases it). As noted by Karl Popper:

"One of the ideas I had discussed in The Poverty [of Historicism] was the influence of a prediction upon the event predicted. I had called this the "Oedipus effect", because the oracle played a most important role in the sequence of events which led to the fulfilment of its prophecy. . . . For a time I though that the existence of the Oedipus effect distinguished the social from the natural sciences. But in biology too -- even in molecular biology --expectations often play a role in bringing about what has been expected" (Karl Popper, Unended Quest: An Intellectual Autobiography, 1976).

The concept is linked to the power of positive thinking. ie I you think it will happen it will.