“Think about the video I showed you. The blue car races through the stop sign and gets into an accident. There were a variety of retail stores in the background. Which coffee shop was on the street? Do you remember? Think about it.”

Frost did. Finally, he said, “I think it was Starbucks.”

“Are you sure?”

“No, but I think so.”

“It wasn’t Seattle’s Best?”

“I don’t think it was. Why? Am I wrong? Was it really Seattle’s Best?”

“Actually, there was no coffee shop on the street at all,” Stein told him. “But if we went over this a few more times, you would swear to me that it was a Starbucks. You’d see it in your head. Most coffee shops are Starbucks, so if someone plants the suggestion that there was a coffee shop, people tend to leap to the conclusion that they saw a Starbucks. Even when it wasn’t there at all.”

“Sneaky.”

“No, it’s just how memory works. How fast do you think the blue car was going when it blew through the stop sign? Want to hazard a guess?”

Frost shrugged. “I’d say thirty-five miles an hour.”

“It was going twenty. The control group in my studies typically guesses twenty-five. You went much higher. Do you know why?”

“I’m sure you’re going to tell me,” Frost said, slightly irritated.

“I’ve described the blue car several times as zipping or racing through the intersection. ‘Blew through the stop sign.’ My characterization influences your brain. You sped up the car because of how I described the incident, not because of what you actually remembered.” Stein leaned forward and added, “In addition, you haven’t corrected me about two important details, even though I’ve made the same mistakes several times.”

“Namely?”

“The car in the video was dark green, not blue. And there was no stop sign at the intersection. It was a yield sign.”

Frost thought back to the video, and he realized to his dismay that he wasn’t sure if she was telling him the truth or not. Stein smiled at him with a slight turn of her lips.

“I’m not trying to make you feel like a fool, Inspector. It’s simply that this is how memory fails us. It’s highly suggestible. If an attorney or police officer did what I did to an accident witness, they’d be very likely to remember a blue car going through a stop sign the next time they tried to recall the incident. And that might be in a courtroom.”

“No offense, Dr. Stein, but you’re not exactly making me feel good about your memory treatments. The whole process sounds dangerous. I read that some of your colleagues have tried to drum you out of the profession because of what you’re doing.”