BASELINE TESTING continues this morning. This is good, I think—another chance to redeem myself. Electrodes always signal pain ahead.

Dr. Angst presides while Nurse Tingle shaves my chest. Predictably, Angst is incredibly intelligent, extremely nice, and as thorough as a watchmaker on Ritalin. A highly respected doctor, he speaks in multisyllabic tongue twisters and would never say, oh, I don't know, "That patient has burning nipples and I have no idea why," when he could say, "That patient has idiopathic areolar dysesthesias."

Dr. Rohlen attaches a small electrode over my heart so that the PeriFlux System 5000, whatever that is, can measure CO₂ concentrations in my skin, while Nurse Tingle plays Bach's Goldberg Variations to lull my heartbeat into its true resting state. Then Angst begins a tedious sequence of questionnaires: a demographic assessment, a Beck Depression Inventory, a Pittsburgh Sleep Quality Index. One question on the Profile of Mood States asks how "listless" I feel right now, and I'm forced to admit, "somewhat."

"What do these have to do with anything?" I ask.

Dr. Angst shifts in his penny loafers. Twenty-five years ago, he says, we believed that our response to pain was hardwired. Stimulation caused nerve cells in the skin to come alive and tiny doors in them to open, allowing positively charged sodium ions to rush inside. The signal traveled nerve to nerve, up the spine, and into the brain, where our CPUs processed it as "an uncomfortable experience that causes anxiety."

"Now we know that pain is felt through a web of systems that is enormously complex," Dr. Angst says. "And it works top to bottom and bottom to top."

Prime examples of this are the familiar placebo effect and the current hot topic in pain, the "nocebo effect." The placebo effect, which can last days, says that if you expect to hurt less, then you will. The brain sends out endorphins, essentially small doses of self-manufactured morphine, to receptors in the central nervous system. Then, when this weakened pain signal makes it back to the brain, the endorphins your gray matter is marinating in produce a sense of well-being or mild euphoria (think runner's high). Visualizing successful post-op recovery or even psyching yourself up before a triathlon is not just a mind game. You're optimizing your whole body to feel less pain.

Conversely, with the nocebo effect, nervousness has been shown to heighten pain sensitivity by as much as 45 percent. "Dios mio!" leads to a release of cholecystokinin, a polypeptide only recently found to exist in the brain that amplifies and heightens pain perception.

"It's the bad guy," Angst explains. "The placebo effect is Spider-Man, and the nocebo effect is . . . the bad guy."

Nice try, Dr. Angst.

"If you're really anxious about falling off your mountain bike," Rohlen says, "then that anxiety is gonna make falling hurt more than it would have."

This is it, the source of all my power: moronic optimism! "This bike saddle fits like a La-Z-Boy!" "Sure I'll test the landing, those are just pillows of snow; no, the pillows of snow weren't rocks!" "Of course you can inner-tube Class IV."

But as far as my pain genes are concerned? The answer comes outside the lab.