As for realism, after everyone saw the success of The Curse of Frankenstein directors began to develop movies based on real life.
Three years after The Curse of Frankenstein, Psycho (1960)
cut into the big screens. It was one of the first horror films based on a true story, so it was scary in a new way. The perception of the horror movie changed. It became a story that could possibly happen in reality, so the viewers were frightened as they could imagine themselves being the main character of such a film one day..
Apart from this, Psycho is also credited as the creator of the slasher genre in horror movies that was about to develop during the next decades.