This time, a Neurosensory Analyzer (a machine that transfers heat to the skin of the forearm) was used to apply increasing levels of uncomfortable heat to the volunteers’ forearm for seven-second intervals. At first the heat was set to arouse only mild discomfort. But it went up from there, peaking at pain levels subjects rated an eight on a ten-point scale, where ten was “unbearable.”
When the scientists compared the two brain scans, what they saw was remarkable. The exact same areas of the brain became activated when subjects relived their heartbreak as when they experienced the highest degree of physical pain—the level that was only a couple of notches below “unbearable.”