If you touch your finger to a hot stove, you know it's going to hurt. However, if you convince yourself beforehand that the pain won't be so bad, you might not suffer as much. According to a recent study, the part of your brain that reacts to severe pain is largely the same part that reacts to expectation of pain. Researchers in this study worked with 10 volunteers, aged 24 to 46. Each volunteer wore a device that gave out 20-second-long pulses of heat to the right leg. There were three levels of heat, producing mild, moderate, or strong pain. During training, the volunteers would first hear a tone, followed by a period of silence, and then feel a heat pulse. They then learned to associate the length of the silent pause with the intensity  of the upcoming heat pulse. The longer the pause, the stronger the heat pulse would be, causing more severe pain. A day or two later, the real experiment began. The researchers found that the parts of the brain involved in learning, memory, emotion, and touch became more active as the volunteers expected higher levels of pain. These were mainly the same areas that became active when participants actually felt pain. Interestingly, when the volunteers expected only mild or moderate pain but experienced severe pain, they reported feeling 28 percent less pain than when they expected severe pain and actually got it. The new study emphasizes that pain has both physical and psychological elements. Understanding how pain works in the mind and brain could eventually give doctors tools for helping people cope with painful medical treatments. Which of the following is true about the pulses of heat in the study?
Each heat pulse lasted for 20 seconds. The pulses were given to the arms of the volunteers. Different devices gave out different levels of heat pulses. There were two levels of heat intensity given to the volunteers.