Observer error
The amount of human (intra-observer) error in selecting landmarks was
very low for both the defended and undefended morphs (defended mean SE =
0.74 x 10-3 [unitless], undefended mean SE = 0.72
x 10-3 [unitless]). This suggests that any
differences in shape measured in the following analyses are the result
of the treatments applied, rather than any observer error.