Results of the MDS calculations are shown in Figure 7, with the entire 27 coherence pair result shown first, with between sex comparisons. A comparative anterior/posterior and male/female set of MDS plots follows in Figure 8. In each case the trajectories for each axis are plotted against age; it is easier to interpret the trajectories in that way rather than as a space curve in 3 dimensions. Because the MDS attempts to represent the distances in its input, the unit of the y axes is the Riemannian distance between between the covariance matrices. The assumption in plotting the trajectories in a comparative manner is that the same axis (by algorithmic order) for each of the sets of covariance matrices represents the same aspect of the developmental process by temporal structure. If the shape of the trajectories along the same axis for different sets of covariance matrices were radically different, the interpretation of the plots would be different from that offered below. Note that the distance between the initial and final matrix in the MDS space is about 2.6 units; this is about a quarter of the estimate of the diameter of sets of comparable covariance matrices discussed in Section 2.3.1.
