The school psychologist mistakenly tells Mickey's parents that their average son is off-the-charts brilliant. Mikey's parents enroll him in extra classes, buy him a chemistry set and take him to lots of museums. Mikey ends up valedictorian of his high school class and gets into Yale. This situation illustrates:

the self-fulfilling prophecy effect

Explanation:

Self-fulfilling prophecy, is a phenomenon that occurs when a false expectations or or mistaken prediction results to actual reality.

In other words, it is a situation in which an individual unknowingly causes a prediction or expectation to become reality, based on the fact that, such individual wants or expects it to be realized.

Hence, in this case, even though, the school psychologist mistakenly tells Mickey's parents that their average son is off-the-charts brilliant, but because the Mikey's parents want the prediction to be true, performs certain actions which later results to the prediction getting realized.