This reminded me of something.

In the book Happiness: Lessons from a New Science by Richard Layard, the author goes into detail about how mood is strongly correlated with differential activation in the two hemispheres of the brain. The left forebrain is more strongly activated than the right forebrain when a person is happy, and the right forebrain is more strongly activated when a person is sad. (Ramachandran mentions that stroke victims with left brain damage frequently become depressed, while ones with right brain damage don't.)

If the left brain interprets data through the perspective of current theories and the right brain forces theory revision, and left brain activation is associated with happiness and right brain activation is associated with unhappiness, what does that say about happiness and rationality?