Two empirical studies identified and tested strengths of dynamic cues that assist listeners in identifying tonal centers. The hypothesis that it is rare intervals, rather than physical properties of tones or static representations such as scales and triads, that play a significant role in a musician's perceptual process of key identification led to the first experimental study of context sufficiency in perception of tonality. Musicians extrapolated tonal centers upon aural presentation of subsets of a major diatonic set with an accuracy mean of 87%. Univalent trichords gave 100% clearer indication of tonal center than did multivalent trichords. The strength of the tonality percept was further explored by examining effects of temporal ordering and by evaluating relationships between formal training and test scores. In a second experiment, listeners judged appropriateness of tonal centers after hearing paired dyads consisting of the rarest intervals in the major set: the tritone and the two minor seconds. Listeners indicated strongest impressions of tonal center when the tritone was heard as a simultaneity. Test performance showed a stronger correlation with listeners' abilities to identify tonal centers in actual music than with listeners' status as musicians or nonmusicians. These results are interpreted as evidence of a widespread cognitive skill that interprets tonality as a system of tonal relations rather than just an abstracted collection of tones or a system governed by the psychophysical attributes of tones.