“The same thing an EEG machine reads,” Dryden said.
Gaul nodded. “If the gibbon is born without NP20, or has it knocked out with a drug, then those older genes are no longer suppressed. They become active genes, and they start altering synaptic patterns in the brain, creating structures that act like natural receivers and transmitters. They let primates read one another’s neural activity. Those same genes, the ones that code for mind reading in gibbons, exist in all the higher primates, too. Chimps. Gorillas. Human beings. We also have NP20 to block them, but where gibbons have only NP20, we have three extra genes that do the same job it does. Like redundant safeties on a bomb. Our evolution seems to have made a point of keeping us out of each other’s heads.”
“But why?” Dryden said. “Why would we evolve away from something like that?”
“We can only guess,” Gaul said, “but I think our guesses are pretty good. Alpha-wave reading probably started tens of millions of years ago, among the ancestors of modern primates. Maybe it was a kind of predator alarm, a way to spread a warning through the group without the risk of making noise. Easy to see the benefit in that. The running guess, though, is that mind reading carried a downside later on, when these animals started getting smarter. Fast-forward to gibbons, with social hierarchies and long-term memory, complex rivalries and emotions, and maybe it’s not a great idea to hear each other’s thoughts. In humans, capable of things like holding grudges for life, it might be a disaster.” Gaul’s face took on a kind of weariness. “Rachel’s a beautiful example.”
“What are you talking about?” Dryden asked.
“You need to know, first, what sets Rachel apart. Why she’s different than Audrey or Sandra, or anyone else they ever had at Detrick. Rachel can do a lot more than just read minds.” Gaul was looking at his hands. Now he looked up and met Dryden’s eyes. “You may already know about her other ability, without realizing it. Going by what you told us a few minutes ago, you’ve seen it in action yourself.”
CHAPTER THIRTY-FIVE
Both Gaul and Harris were watching him now, waiting for his response. He didn’t have one. He had no idea what Gaul was talking about.
“You said someone gave you two a ride out of Fresno,” Gaul said. “You and Rachel were in the trunk. A police officer demanded to search it, and then for no obvious reason he just gave up and waved the driver through.”
“I thought it was strange,” Dryden said. “What does it have to do with Rachel?”
“Everything,” Gaul said.
Harris leaned forward and spoke softly. “She doesn’t just read minds, Sam. She can influence them, too. Right now she doesn’t remember that she can do it, but she can.”
“The mind reading is passive,” Gaul said. “Like seeing and hearing. It just happens. But the other part, influencing other people’s minds, is different. It takes concentration and focus, and complicated mental routines. Same as playing chess or balancing a spreadsheet. Rachel spent years building up the ability, and at the moment she can’t recall any of it.”
“Based on observations of Rachel in captivity, in El Sedero,” Harris said, “these guys think she can exert a small amount of control even now, but only subconsciously. The effect would be minor, and it would only happen if she was emotionally stressed. She wouldn’t even realize she was doing it.”
Dryden thought of the checkpoint in Fresno: Dena trying to talk her way past the cop, digging the hole deeper by the second; Rachel beside him in the dark, gripping his hand, her body shaking.
Then the cop had just let them go.
I don’t get it, Dena had said. He was staring right at me and then … he just changed his mind.
“Jesus,” Dryden said.