Remember that A. robustus and A. boisei did not have large brains. They had specialized features
for chewing tough plant fibers. The importance of features other
than brain size is evident as you view the top of the cranium of an A.
robustus. Also keep in mind the nickname: the "human cuisinart".
It is quite fitting for these hominids whose specialization may have provided
for their success in the short-term. It did not suit them for the long-term
success of other hominids with a more generalized adaptation.
Test your understanding on this A. boisei. 
