In Augmented Reality (AR) apps while you are capturing your sorroundings with your phone/tablet's camera in real-time, the application can add virtual scenes and characters to the footage. To tell the program where is the surface where you want to projectile the scene, you usually you need a printed or drawn card with special symbols that the program can recognize. Fortunately in the case of these apps you won't need them, because Sony used it's Face Recognition Technology and SmartAR Engine that automatically detect faces and 3D environments around you to decorate them with fun AR items.
AR effects is a collection of funny mini apps. In this video you can watch the features of the app:
The second app is Horror. Basicly, it's a face recognition program with "horroristic" features.
The program offers bulit-in face motion tracking function, so you shouldn't stand still for minutes in one place to shoot these extremely funny pictures.