The relative stability of a tone may depend to some degree on its treatment within a particular compositional context as, for example, by the degree to which it is stressed metrically or rhythmically, its place in the contour of a melodic line, its pitch range, and the timbre and dynamics with which it is sounded. However, it is presumed that there is a more abstract, invariant hierarchy of stability that is typical of a musical style more generally, and that this more abstract hierarchy is an important characteristic contributing to the perceived stability of each tone within a complex musical sequence. In this connection, Bharucha (1984b, p. 421) makes the following useful distinction between "event hierarchies" and "tonal hierarchies":