A groundbreaking new study has reignited the debate over whether political ideology is linked to brain structure.

Forget crowd sizes — a new study confirms that conservatives boast slightly larger amygdalas, the part of the brain that plays a key role in identifying and reacting to potential threats, compared with liberals.

The roots of conservatism may be buried deep in the brain, scientists believe, after finding right-wingers have more gray matter in an area linked to threats and uncertainty.