Is there anything special about humans in evolution?

• Relative increases in brain size are not general across the brain but occur specifically in neocortex and related structures ... extending a trend seen across the vertebrates and mammals, probably with some additional neocortical localization in the human lineage (not readily observable in endocasts)
  

• Neocortex enhances both the capacity to make use of variability in behavior and the capacity to deal with resulting ambiguities and uncertainties. Could this be "behavioral complexity"?

• An increase in neocortical function could itself become a selection pressure for increases in neocortical function, resulting in a positive feedback loop.

• Brain structure is likely to be more significant than brain size. And the adaptive value of a Runaway Brain may hold only in the presence of other such brains.

• Positive feedback loops of this sort may further help to account for directional changes in evolution, such as increases in complexity.

• Enhanced variability in the brain does the same thing that evolution does, generates and explores novel possibilities (plays), but makes it possible to do so more rapidly than variability based on genetic variation.