 When someone presses a hand against the grill, he or she experiences the illusion of burning heat.But if the person presses against only a cool bar, only coolness is experienced; if the person presses against only a warm bar, only warmth is experienced.Researchers have used the illusion to demonstrate that burning pain sensation is in fact a mixture of both cold and heat pain and that it is only the inhibition of the cold pain "channel" that reveals the heat component.