Isn't weightlessness the obvious choice?

Perhaps it is change that stimulates intelligence, and helps organisms to
leverage neuroplasticity.

There is a theory that humans are descended for aquatic apes!

Then:

Relative intelligence of dolphins explained by:
Sea -> Land -> Sea

Still greater intelligence of humans explained by:
Sea -> Land -> Sea -> Land

(This will also explain how shortly we will be the dumbest creatures on
planet earth - with a fully automated environment where no one has to think
too much)

Neuroplasticity: http://en.wikipedia.org/wiki/Neuroplasticity

Aquatic Apes: http://en.wikipedia.org/wiki/Aquatic_ape_hypothesis

Regards
Selvaraj

2010/1/13 kenjopp