People with left wing views may have their political opinions controlled by a “liberal gene”, according to scientists.
In people who are naturally outgoing, the feature encourages them to seek out companions with unconventional views as they grow up.
This in turn means they tend to form less conventional political viewpoints as adults, according to the study by the University of California and Harvard.
The research, based on 2,000 Americans, is published in the Journal of Politics.
It found those with a strain of the DRD4 gene seek out “novelty”–such as people and lifestyles which are different to the ones they are used to.
This leads them to have more liberal political opinions, it found.
The person’s age, ethnicity, gender or culture appeared to make no difference–it was the gene which counts.
DRD4 is controlled by dopamine which affects the way the brain deals with emotions, pleasure and pain and can therefore influence personality traits.
UC Professor James Fowler said: “It is the crucial interaction of two factors–the genetic predisposition and the environmental condition of having many friends in adolescence–that is associated with being more liberal.
“These findings suggest that political affiliation is not based solely on the kind of social environment people experience.”
[“Friendships Moderate an Association between a Dopamine Gene Variant and Political Ideology,” by Jaime E. Settle, Christopher T. Dawes, Nicholas A. Christakis and James H. Fowler, can be read here.]