The angry cadet interrupted. “You’re telling us that none of the witnesses could hear what direction the shot came from?”
“The brain’s greatest strength, the ability to create instant connections, can be its greatest weakness. All the witnesses thought they saw a gun in the hand of at least one of the participants in the confrontation. A moment later they heard a gunshot. They all connected the sound with the visual image. Their brains discounted the directional component of their hearing in favor of visual logic: you see what you think is a gun, you hear a gunshot, your brain automatically puts them together. And your brain is almost always right.”
The bodybuilder was frowning. “But didn’t you say that neither one of them actually had a gun? So . . . the witnesses who claimed they saw one . . . what did they actually see?”
“A cell phone.”
That led to the longest silence so far—no doubt reminding many in the room of the tragic news stories involving that very mistake being made by stressed police officers.
The farm-boy cadet looked appalled. “So, the witnesses were wrong about everything?”
“It happens,” said Gurney.
A cadet directly in front of him raised his hand. “What’s the bottom line on this? It sounds like we shouldn’t even bother taking eyewitness statements.”
“Statements can be helpful,” said Gurney. “But the bottom line is caution. Keep an open mind. Remember that eyewitnesses can be very credible—and very inaccurate. And the problem carries over into courtrooms. Eyewitness testimony, which is actually the least reliable evidence, is the most persuasive. And it’s not because anyone is lying. The fact is, people often see things that aren’t really there.”
The angry cadet piped up. “Mental cases, maybe. Idiots who don’t pay attention. Trust me—when I look at something, I see what’s there.”
“I’m glad to hear that,” said Gurney with a pleasant smile. “It’s a perfect introduction to a pair of animations I think you’ll enjoy.” He opened a laptop computer on the podium and switched on the projector.
“The first ten-second animation you’ll see shows a large blue ball bouncing across the screen. There are some numbers printed on the ball. The other animation will show a large green ball, also with numbers on it. Apart from those numbers, the balls may have other differences between them in size, surface texture, and the way they bounce. Pay close attention and see how many differences you’re able to notice.”
Gurney tapped a key on the laptop, and what looked like a large beach ball bounced slowly across the screen behind him.
“Next, the green ball,” said Gurney, again tapping a key.
After it completed its passage across the screen, he switched off the projector.
“Okay, now tell me about the differences you noticed. I want to hear from everyone, but first from you,” said Gurney, turning toward his challenger.
There was a new uncertainty in his eyes. “Some of the numbers on the balls might have been different.”
Gurney nodded encouragingly. “Anything else?”
“The green one bounced a little faster than the blue one.”
“What else?”
The angry cadet responded with a shrug.
“So,” persisted Gurney, “different numbers, different bouncing speeds. Any other differences between the balls?”
“Obviously, the colors.”
Gurney then addressed the same question to the other cadets and listened to their descriptions of the differences in the speeds, sizes, surface textures, and numbers on each ball.
He waited until they’d all offered their opinions.
“Now, I have an apology to make. I misled you—in the same way that I was misled when I was first shown the animation of the bouncing ball.”
He paused again. “Did anyone notice what I just said?”
At first no one responded. Then the bodybuilder’s eyes widened. “You said animation this time. Not animations.”
“Correct.”
In response to the perplexed faces around the room, he continued, “There was only one bouncing ball. I showed you the same animation twice.”
His challenger with the sour mouth said, “But you obviously messed with the color to make the ball look blue the first time and green the second. So it doesn’t prove anything, except that you lied.”
The room got very quiet. Gurney smiled. “I messed with your brain, not the color. The color of the animated ball occupies the midpoint between blue and green on the color spectrum. Because of what I told you at the beginning, you expected the first ball to be blue and the second to be green. And because that’s what you expected, you saw it the first time as bluer than it was and the next time as greener than it was. If you took a polygraph test on the two colors you saw, you would have passed. You would have been telling the truth, as you saw it. That’s my point. Witnesses may be telling you the truth about what they saw, but that truth may exist only in their own heads. And a polygraph test only measures the honesty of someone’s recollection, not its accuracy.”
A raspy-voiced question came from the back of the room. “So what kind of evidence are we supposed to trust?”
“DNA. Fingerprints. Credit card and bank records. Phone records, especially those with GPS data. Emails, texts, and social media posts can also be useful in establishing motives, relationships, and states of mind.”
“How about surveillance videos?” someone asked.
“Absolutely,” said Gurney. “The fact is, I’d take one high-quality video over a dozen eyewitness reports anytime. Cameras are basically pure optic nerves. They have no prejudices, no imagination, no desire to fill in the blanks. Unlike humans, they only see what’s actually there. But be careful when you view those videos.”
“Careful of what?” someone else asked.
“Careful that your own brain doesn’t screw up what the camera got right.”
2
After giving a reading assignment on the subject of his next lecture, Gurney ended the class and made his way along a colorless, fluorescent-lit corridor to the office of Harris Schneider, the academy’s part-time psychologist and occasional trauma counselor.
He was a small, middle-aged man with a large salt-and-pepper mustache never quite free of crumbs, a brown tweed jacket with elbow patches, and a briar pipe, overflowing with tobacco, that he always seemed on the verge of lighting. He listened as Gurney expressed his concern about the angry cadet in his seminar—the fact that he was already exhibiting the reflexive hostility characteristic of a mid-career burnout.
Schneider cleared his throat. “Yes, I know. Unfortunate. Already on our radar. Not good.” He nodded, as if agreeing with himself. “Appropriate action will be taken at the appropriate time.” He flashed a quick smile, as if pleased with his command of the situation. He glanced at the full bowl of his pipe, took a vintage chrome lighter out of his jacket pocket, and placed it on the desk in front of him—a gesture that, along with a sniffle and another clearing of his throat, signified that the meeting was concluded.
Gurney was tempted to restate his concern in more vivid terms—describing the consequences he’d witnessed when guns and badges had been given to angry men. But surely Schneider knew what could happen as well as he did. He thanked the man for his time, perhaps a bit too brusquely, and headed for the parking lot.