Veronica Shannon was pacing back and forth in her lab. Mary was sitting on one of the office’s two identical chairs; Ponter had found his chair’s width between its metal arms too narrow for his bulk, and so had perched his rear on the edge of Veronica’s surprisingly tidy desk.

“Do you know anything about psychology, Ponter?” asked Veronica, her hands clasped behind her narrow back.

“Some,” Ponter said. “I studied it when I was learning about computer science at the Academy. It was—what would you call it?—something I had to study along with artificial intelligence.”

“A co-requisite,” supplied Mary.

“In every freshman psych course,” said Veronica, “humans here learn about B. F. Skinner.”

Mary nodded; she’d taken an introductory psychology course herself. “Behaviorism, right?”

“Right,” said Veronica. “Operant conditioning; reinforcement and punishment.”

“Like training dogs,” said Ponter.

“Just so,” said Veronica. She stopped pacing. “Now, please, Mary, don’t say a word. I want to hear Ponter’s response to this without any influence from you.”

Mary nodded.

“All right, Ponter,” said Veronica. “Do you remember your psych studies?”

“No, not really.”

The young redhead looked disappointed.

“But I do,” said Hak, through its external speaker, in its synthesized male voice. “Or, more precisely, I have the equivalent of a textbook on psychology loaded into my memory. It helps me to advise Ponter when he is making an idiot of himself.”

Ponter grinned sheepishly.

“Excellent,” said Veronica. “Okay, here’s the question: what’s the best way to ingrain a behavior into a person? Not something you want to extinguish, but something you want to foster.”

“Reward,” said Hak.

“Reward, yes! But what kind of reward?”

“Consistent.”

Veronica looked as though something incredibly significant had just transpired. “Consistent,” she repeated, as if it were the key to everything. “Are you sure? Are you absolutely sure?”

“Yes,” said Hak, sounding as puzzled as he ever got.

“It’s not here, you know,” said Veronica. “Consistent reward is not the best way to ingrain a behavior.”

Mary frowned. She’d doubtless known the right answer at one time, but couldn’t dredge it up after all these years. Fortunately, Ponter himself asked the question Veronica was waiting for. “Well, then, what is the best way to ingrain a behavior among your kind of humans?”

“Intermittent reward,” said Veronica triumphantly.

Ponter frowned. “You mean sometimes rewarding the desired behavior, and sometimes not?”

“Just so!” said Veronica. “That’s precisely right!”

“But that does not make sense,” said Ponter.

“Of course not,” agreed Veronica, grinning widely. “It’s one of the strangest things about Homo sapiens psychology. But it’s absolutely true. The classic example is gambling: if we always win at a game, the game becomes boring for us. But if we only win some of the time, it can become addictive. Or it’s like kids whining to their parents: ‘Buy me this toy!’ ‘Let me stay up late!’ ‘Drive me to the mall.’ It’s the behavior parents hate the most from their kids, but the kids can’t help themselves—not because the whining always works, but because it sometimes works. The unpredictability makes it irresistible for us.”

“That is crazy,” said Ponter.

“Not here,” said Veronica. “Not by definition: the behavior of the majority is never crazy.”

“But…but surely it is simply irritating not to have a predictable outcome.”

“You’d think,” agreed Veronica amiably. “But, again, it’s not—not for us.”

Mary found herself fascinated. “You’re obviously on to something, Veronica. What is it?”

“Everything we’re doing here at the Neuroscience Research Group has been about explaining the classic religious experience. But there are lots of believers who’ve never had a religious experience, and yet they still believe. That’s the hole in our work, the missing piece in a comprehensive explanation of why Homo sapiens believe in God. But this is the answer—do you see? It’s this psychology of reinforcement—this bit of the way our brains are programmed—that makes us susceptible to belief in God. If there really was a God, a rational species would expect rational, predictable behavior from him. But we don’t get that. Sometimes, it seems as though God protects certain people, and at other times, he’ll let a nun fall down an open elevator shaft. There’s no rhyme or reason to it, and so we say—”

Mary was nodding, and she finished the thought for Veronica. “We say, ‘The Lord works in mysterious ways.’ ”

“Just so!” crowed Veronica. “Prayers aren’t always answered, but people go right on praying. But Ponter’s people aren’t wired like that.” She turned to the Neanderthal. “Are you?”

“No,” said Ponter. “I do not need Hak to tell me that this is not the way we behave. If the result is not predictable—if a pattern cannot be discerned—we discard the behavior as pointless.”

“But we don’t,” said Veronica, rubbing her hands together. Mary could see she had the same “Cover of Science, here I come!” expression Mary herself had worn years ago, when she’d succeeded in extracting DNA from the Neanderthal type specimen in Germany. Veronica beamed at Ponter, then at Mary. “Even if there is no pattern, we convince ourselves that there’s some underlying logic to it all. That’s why we don’t just make up stories about gods; we actually believe them.”

The religious Mary had shifted entirely to the background; this was making the scientist in her have its own peak experience. “Are you sure about this, Veronica? Because if you are—”

“Oh, I am; I am. There’s a famous experiment—I’ll e-mail you the citation. It had two groups of people playing a game on a grid, the rules of which hadn’t been explained to the players. All they knew in advance was they’d get points for good moves and no points for bad moves. Well, for one set of players, points were given for successfully marking every other space in the lower-right corner of the grid—and, of course, after enough turns, the players easily figured that out, and could win the game every time. But the second set of players were rewarded points randomly: whether they got points or not had no relation to what moves they made. But those players also came up with rules that they said governed the game, and they were convinced that by following those rules, they were likely to do better.”

“Really?” said Ponter. “I would simply lose interest in the game.”

“No doubt you would,” said Veronica, smiling broadly. “But we would find it fascinating.”

“Or irritating,” said Mary.

“Irritating, yes! Meaning it would bug us—because we just can’t accept that there’s no underlying design to things.” Veronica looked at Ponter. “Can I try another little test? Again, Mary, if you don’t mind, please don’t say anything. Ponter, do you know what I mean when I talk about flipping a coin?”

Ponter didn’t, so Veronica demonstrated with a loonie she fished from a pocket of her lab coat. When Ponter nodded that he understood, the skinny redhead went on. “All right, if I flip this coin twenty times, and all twenty times it happens to come up heads, what are the chances it will come up heads again on the twenty-first try?”

Ponter didn’t hesitate. “One-to-one.”

“Just so! Or to put it the way we would, fifty-fifty, right? An even chance.”

Ponter nodded.

“Now, Mary, I’m sure you know that Ponter is absolutely right: it doesn’t matter how many times heads has come up in succession before the current flip, assuming the coin isn’t unbalanced. The odds that the next flip will be heads are always fifty-fifty. But when I ask first-year psych students this question, most of them think the odds must be astronomically against getting yet another heads. At some fundamental level, our brains are wired to impute motivation to random events. That’s why even those who don’t ever have the kind of experience we just manufactured for you, Mary, still see God’s handiwork in what’s really just randomness.”