In the basic experiments, the eleme

In the basic experiments, the elements of interest (tones or chords) are presented singly or in pairs following a musical unit, such as a scale or chord cadence, that would be expected to establish a particular key quite unambiguously. The listeners are required to judge, using a numerical scale, how related the presented elements are, either to each other, or to the established key. Some justification for this procedure is needed. The rationale for presenting tones in key-defining contexts is that key, or tonality, has important implications for the way in which tones and chords are used in simultaneous and successive combinations. Moreover, the key establishes hierarchies of structural significance for tones and chords. Certain of these elements are more central or important within the tonality, with other elements functioning in relation to these central elements. It will be argued that this kind of hierarchical ordering is an essential point of contact between the way in which tonal-harmonic music is constructed and the psychological system that organizes, interprets, and remembers music of this style