This 2015 study was of the collective behavior of sheep, to:

“Alternate slow group dispersion in space with rapid aggregation phenomena induced by a sudden behavioral shift at the individual level.

The behavioral shift occurs without any perceived threat in the neighborhood, resulting in a spontaneous transition at the collective level that can be interpreted as a consequence of random individual decisions.”

The researchers’ assertion that the “sudden behavioral shift” was due to “random individual decisions” had a lot to do with facilitating their model.

If the researchers had taken individual neurobiological measurements, they may have found that these were non-random actions, deterministically driven by instincts or needs, instead of “random individual decisions.”

http://www.pnas.org/content/112/41/12729.full “Intermittent collective dynamics emerge from conflicting imperatives in sheep herds”