Fig. 7. Time course of changes in the direction of the initial segment. (A,B) The change of initial heading with experience is shown for individual ants after a 45° switch (A) or a 90° switch (B) between F1 and F2. The trace for each ant is a smoothed version of the raw headings using a median filter (window size, three runs). In A and B the upper and lower shaded areas represent the ranges over which headings are categorised as F1 and F2, respectively.