Solso and mccarthy (1981) asked subjects to remember a set of faces created using police identikits. subjects were later tested on some of these studied faces as well as some new faces, including one composed by averaging all the studied faces. the critical finding was that

Solso and McCarthy did the prototype effect experiment (1981) combining hair, eyes, nose + chin, and mouth and produced few examples variating some of those components. Prototype effect is a tendency to recognize the face by corresponding to the central value of a series of seen faces, even when this central value (prototype) has not been seen. The critical finding was that subjects confidently misidentified the prototype face with formerly seen face. The results were the same in second experiment as well.

stable food supply,social structure, government,religion,culture/art,technology and writing/language;