Fig. 2. Median values for the mean displacement of the track from the direct line of approach for individual chicks. Values are shown for three reference points in the chick's journey to the dish: distant (DIST), mid (MID) and close (CLOSE) (see Materials and methods). Displacements to the chick's left (which would bring the right eye to bear on the dish) are shown as positive. Displacements to the right (which would bring the left eye to bear) are shown as negative. These are largely confined to NOL chicks. Almost all conditions departed significantly at all three points from an even distribution of right and left displacement: P values for DIST, MID and CLOSE, respectively, are: NOL, P=0.004, P=0.013, P=0.024; SL, P=0.018, P=0.044, P=0.0001; UL, P=0.001, P=0.002, P=0.040; STR, P=0.016, P=0.016, P=0.066. See Fig. 1 legend for description of dish conditions and Materials and methods for details of chick numbers and trials.