From the source:

First, they were attached to equipment to measure skin conductivity, which rises with emotional stress as the moisture level in skin goes up. Each participant was shown threatening images, such as a bloody face interspersed with innocuous pictures of things such as bunnies, and rise in skin conductance in response to the shocking image was measured. The other measure was the involuntary eye blink that people have in response to something startling, such as a sudden loud noise. The scientists measured the amplitude of blinks via electrodes that detected muscle contractions under people's eyes.

Subjects who had expressed a high level of support for policies "protecting the social unit" showed a much larger change in skin conductance in response to alarming photos than those who didn't support such policies.

Personal addendum: I disagree with the use of the word "dictate"; it should have been "indicate"