According to Rees' study, conservatives have larger amygdalae than progressives; in progressives there is more grey matter in an area of the cortex known as the anterior cingulate cortex. The amygdala is a very ancient area of the brain, involved in learning primitive fight or flight responses. Even frogs have them. The anterior cingulate is newer, and does some interesting stuff - a typical task used to test its function is to ask someone to identify the color used to print a word, for example:
The anterior cingulate is very active when we're making a conscious effort to understand things or learn new stuff.
On the down-under parts of the internet, Rees' study hasn't had much attention. According to Piers Akerman it helps us understand why conservative voters have more common sense than left-wingers - they're more in touch with the ancient amphibian wisdom of the amygdala. And it's thanks to those same left-wingers, voting with them new-fangled cortical parts of the brain that we still have - by a small margin - an ALP government. Then there's this piece of ancient amphibian wisdom at Quadrant which is where I learnt about the study inthe first place.
If the study shows one thing, it's that it's completely inappropriate to refer to conservatives as dinosaurs. The evolutionary origins of conservative thinking are much more ancient than that..