 In a number of models of environmental decoherence, however, it is obvious what the dynamical behaviour should be even at the level of individual components. Specifically, in models where the preferred states are coherent states, comparison of the master equation for the reduced state of the system with the evolution of a classical Liouville distribution suggests that the trajectories of individual components in fact approximate surprisingly well the corresponding Newtonian trajectories. Intuitively, one can explain this by noting that the preferred states (which are wave packets that are narrow in position and remain so because they are also narrow in momentum) are the states that tend to get least entangled with the environment. Therefore they will tend to follow the Schrödinger equation more or less undisturbed. But, as a matter of fact, narrow wave packets follow approximately Newtonian trajectories, at least if the external potentials in which they move are uniform enough across the width of the packets (results of this kind are known as ‘Ehrenfest theorems’). Thus, the resulting trajectories will be close to Newtonian ones (on the relevant  scales).[11]