Before revision:  Our results show that in collective behavior spatio-temporal dynamics are important , and that individual-level selection does not in general provide a robust proximate mechanism in support of the ``criticality hypothesis'' in animal groups .
After revision:  Our results demonstrate the decisive role of spatio-temporal phenomena in collective behavior spatio-temporal dynamics are important , and that individual-level selection does not in general provide a robust proximate mechanism in support of the ``criticality hypothesis'' in animal groups .