The importance in pitch recognition of the so-called tonal attributes of quality and vocality, defined by Revesz as that which recurs at every octave and that which is different in different octaves, has been emphasized by a number of writers. Max Meyer, writing in 1914, believes that the distinction between tonality and vocality is essential for an understanding of memory for absolute pitch. Revesz states that there may be several kinds of memories for absolute pitch, in which one or the other or both attributes play a part. A musical interval can be either a span in vocality, or a relation of tonality, or both.