Biological Cybernetics 78, 377-387 (1998)

A conceptual approach to the magical number 7

Willy Wong, Shuji Mori

The traditional paradigm for studying the magical number is questioned and a new approach is sought in order to obtain a better conceptual understanding of this phenomenon. Building on earlier work, a theory is proposed whereby the results of an absolute identification experiment can be characterized by a single parameter to a reasonable approximation. This parameter is the variance in the subject's response to a sensory input. By reducing the magical number to a single parameter, we see that the value of the upper limit in information transmission depends not so much on the absolute magnitude of the response error, but actually on how fast this error grows with range. The theory also predicts a little known characteristic of the magical number. If this prediction can be demonstrated experimentally, we shall need to reinterpret the magical number.