Is a bigger brain a better brain though?
It was almost two decades ago when my junior high school science teacher was talking about a study done where they compared the size of people's brains and compared intelligence and (if I remember correctly) there was no correlation between the size of a person’s brain and their intelligence.
Even if you assume that size of a component of your brain is related to intelligence in that area, there is nothing saying that 'bigger is better'. After all, a person may have a brain that is highly efficient in processing some form of stimulus and may be able to deal with this stimulus in more time with less input at a smaller physical size.
Finally, I would like to see a comparison between sizes of these portions of the brain based on ethnic background, age, sex, highest educational level achieved, income level and as many other classifications as can be thought of. After all, the demographics of political parties are often quite a bit different and a small portion of either parties supporters could skew the total results quite a bit.