"Not if you add in the earrings." They shouldn't joke about this, but the alternative was to take it very seriously. She said, "It's weird. I know the monitor's not there anymore, but I can still feel it." "Signal detection theory." He straightened the straw again. "Your perceptual systems are biased toward the monitor touching your skin. More often, people experience the sensation with their phones. They feel it vibrating even when it's not."