Using functional magnetic resonance imaging (fMRI), researchers revealed that the right amygdala lit up when subjects looked at an angular object, such as a square dish or sharp-cornered chair, but stayed quiet when they looked at a curved version of the same object. They speculate that because sharp objects in our environment, such as teeth or thorns, represented potential sources of danger to our ancestors, we have evolved to respond to angled contours with an unconscious level of caution.
