How would you define psychological realism?

The novels that grow out of psychological realism are considered to be character-driven and place special emphasis on the interior life of the protagonist or other point-of-view characters. In these novels, the actual plot is not only secondary, but arises from the motives, fears, and reactions of characters to the dilemmas that confront them. This perspective can be clearly seen in Shakespeare's Hamlet and Richardson's Pamela.