P. boisei choose to ignore evolution.

A study by the University of Arkansas has found that our robust extinct relative Paranthropus boisei (also known as the nutcracker man) ate mostly fruit even it was very well adapted to much harder foods like roots and nuts. This introduces an interesting evolutionary paradox: they evolved to ate hard stuff but then they found they could also exploit resources they were not specialized for and choose them preferentially.

It seems that after all, our cousin was more intrinsecally adaptative than simply made-by-evolution. Just like us.

Source: Science Daily: New findings challenge conventional ideas on evolution of human diet and natural selection.