“How?”

“How?” Distracted, she looked back at him.

“How can you tell one from the other?”

“Just basic observation. I can look out of my window onto the waterfront. The tourists are couples, more likely families, occasionally a single. They stroll, or they shop. They rent a boat. They interact with each other, the ones in their group. They’re out of their milieu. Most will have camera, map, maybe binoculars. Most of the natives have a purpose for being there. A job, an errand. They might stop and say hello to a neighbor. You can see them easing back on their way as they end the conversation.”

“Why are you watching from the window?”

“I don’t understand the question.”

“Why aren’t you down on the waterfront?”

“I have been. But you usually get a purer study when you, the observer, aren’t part of the scene.”

“I’d think you’d get more varied and more personal input if you were.” He glanced up as the waiter arrived to top off their wine and offer them dessert.

“Just coffee,” Sybill decided. “Decaf.”

“The same.” Phillip leaned forward. “In your book, the section on isolation as a survival technique, the example you used of having someone lying on the sidewalk. How people would look away, walk around. Some might hesitate before hurrying past.”

“Noninvolvement. Disassociation.”

“Exactly. But one person would eventually stop, try to help. Once one person broke the isolation, others would begin to stop, too.”

“Once the isolation is breached, it becomes easier, even necessary for others to join. It’s the first step that’s the most difficult. I conducted that study in New York and London and Budapest, all with similar results. It follows the urban survival technique of avoiding eye contact on the street, of blocking the homeless out of our line of sight.”

“What makes that first person who stops to help different from everyone else?”

“Their survival instincts aren’t as well honed as their compassion. Or their impulse button is more easily pushed.”

“Yeah, that. And they’re involved. They’re not just walking through, not just there. They’re involved.”

“And you think that because I observe, I’m not.”

“I don’t know. But I think that observing from a distance isn’t nearly as rewarding as experiencing up close.”

“Observing’s what I do, and I find it rewarding.”

He slid closer and kept his eyes on hers, ignoring the waiter who tidily served their coffee. “But you’re a scientist. You experiment. Why don’t you give experiencing a try? With me.”

She looked down, watched his fingertip toy with hers. And felt the slow heat of response creep into her blood. “That’s a very novel, if roundabout, way of suggesting that I sleep with you.”

“Actually, that wasn’t what I meant—though if the answer’s yes, I’m all for it.” He flashed her a grin as she shifted her gaze warily to his. “I was going to suggest that we take a walk on the waterfront when we’ve finished our coffee. But if you’d rather sleep with me, we can be in your hotel room in, oh, five minutes flat.”