A technique called neuromarketing is increasingly being used by political campaigns around the world to enable them to target voters with precision.  

Instead of traditional focus groups, researchers gather physical data like facial expressions, brain activity and physiological changes to create marketing materials precisely crafted to individual voters' interests and preferences. 

Neuromarketing is currrently being used in political campaigns in Mexico, Turkey, Poland and Colombia, among others.

But its use is limited in the US... For now. 

Kevin Randall from the New York Times explained its growing use to A Martinez.

To listen to the segment, click on the audio above.