The quick decisions made by a quarterback on a football field provide a window into the inner workings of the brain. In the space of a few frenetic seconds, before a linebacker crushes him into the ground, an NFL quarterback has to make a series of hard choices. The pocket is collapsing around him — the pocket begins to collapse before it exists — but he can’t flinch or wince. His eyes must stay focused downfield, looking for some meaningful sign amid the action, an open man on a crowded field. Throwing the ball is the easy part.
These passing decisions happen so fast they don’t even seem like decisions. We are used to seeing football on television, captured by the cameras far above the grassy stage. From this distant perspective, the players appear to be moving in some sort of violent ballet; the sport looks exquisitely choreographed. You can see the receivers spread the zone and watch the pocket slowly disintegrate. It’s easy to detect the weak spots of the defense and find the target with man-on-man coverage. You can tell which linebackers bought the play-action fake and see the cornerback racing in on the blitz. When you watch the game from this omniscient angle — coaches call it "the eye in the sky" — it appears as if the quarterback is simply following orders, as if he knows where he is going to throw the ball before the play begins.

But this view of the game is deeply misleading. After the ball is snapped, the ordered sequence of neat X’s and O’s that fill the spiral-bound playbook degenerates into a street brawl. There’s a symphony of grunts and groans and the meaty echoes of fat men hitting hard ground. Receivers get pushed off their routes, passing angles get cut off, and inside blitzes derail the best intentions. The offensive line is an unpredictable wrestling match. Before the quarterback can make an effective decision, he needs to assimilate all of this new information and be aware of the approximate location of every player on the field.

The savage chaos of the game, the way every play is a mixture of careful planning and risky improvisation, is what makes the job of an NFL quarterback so difficult. Even while he’s immersed in the violence — the defensive line clawing at his body — the quarterback has to stand still and concentrate. He needs to look past the mayhem and make sense of all the moving bodies. Where is his receiver going? Will the safety break toward the ball? Is the linebacker going to drop back into coverage? Did his tight end pick up the blitz? Before a pass can be thrown — before the open man can be found — all of these questions need to be answered. Each pass is really a guess, a hypothesis launched into the air, but the best quarterbacks find ways to make better guesses. What separates Tom Brady and Joe Montana and Peyton Manning and John Elway and the other great quarterbacks of the modern NFL era from the rest is their ability to find the right receiver at the right time. (The Patriots like to pass out of a five-wide formation, which means that Brady often checks off five different receivers before he decides where to throw the ball.) No other team sport is so dependent on the judgment of a single player.

NFL scouts take the decision-making skills of quarterbacks very seriously. The league requires that every player in the draft take the Wonderlic intelligence test, which is essentially a shorter version of the standard IQ test. The test is twelve minutes long and consists of fifty questions that get progressively harder as the test goes along. Here’s an example of an easy Wonderlic question:

"Paper sells for 21 cents per pad. What will four pads cost?"

And here’s a hard Wonderlic question:

"Three individuals form a partnership and agree to divide the profits equally. X invests $9,000, Y invests $7,000, Z invests $4,000. If the profits are $4,800, how much less does X receive than if the profits were divided in proportion to the amount invested?"

The underlying thesis of the Wonderlic test is that players who are better at math and logic problems will make better decisions in the pocket. At first glance, this seems like a reasonable assumption. No other position in sports requires such extreme cognitive talents. Successful quarterbacks need to memorize hundreds of offensive plays and dozens of different defensive formations. They need to spend hours studying game tape of their opponents and be able to put that knowledge to use on the field. In many instances, quarterbacks are even responsible for changing plays at the line of scrimmage. They are like coaches with shoulder pads.

As a result, an NFL team starts to get nervous when a quarterback’s score on the Wonderlic test is too far below the average for the position. For quarterbacks, the average is 25. (In comparison, the average score for computer programmers is 28. Janitors, on average, score 15, as do running backs.) Vince Young, the star quarterback from the University of Texas, reportedly scored a 6 on the test, which led many teams to publicly question his ability to succeed in the NFL.

But Young ended up excelling in the pros. And he isn’t the only quarterback who achieved success despite a poor Wonderlic score. Dan Marino scored 14. Brett Favre’s Wonderlic score was 22, and Randall Cunningham and Terry Bradshaw both scored 15. All of these quarterbacks have been or will be inducted into the Hall of Fame. (In recent years, Favre has surpassed many of the passing records once held by Marino, such as most passing yards and touchdowns in a career.) Furthermore, several quarterbacks with unusually high Wonderlic scores — players like Alex Smith and Matt Leinart, who both scored above 35 on the test and were top-ten picks in the 2005 NFL draft — have struggled in the NFL, largely because they make poor decisions on the field.

The reason there is virtually no correlation between the results of the Wonderlic and the success of quarterbacks in the NFL is that finding the open man involves a very different set of decision-making skills than solving an algebra problem. While quarterbacks need to grapple with complexity — the typical offensive playbook is several inches thick — they don’t make sense of the football field the way they make sense of questions on a multiple-choice exam. The Wonderlic measures a specific kind of thought process, but the best quarterbacks don’t think in the pocket. There isn’t time.

Take that pass to Troy Brown. Brady’s decision depended on a long list of variables. He needed to know that the linebacker wouldn’t fall back into coverage and that there were no cornerbacks in the area waiting for an interception. After that, he had to calculate the ideal place to hit Brown with the ball so that Brown would have plenty of room to run after the catch. Then he needed to figure out how to make a throw without hitting the defensive lineman blocking his passing lane. If Brady were forced to consciously analyze this decision — if he treated it like a question on the Wonderlic test — then every pass would require a lot of complicated trigonometry as he computed his passing angles on the plane of the football field. But how can you contemplate the math when five angry linemen are running straight at you? The answer is simple: you can’t. If a quarterback hesitates for even a split second, he is going to get sacked.

So how does a quarterback do it? How does he make a decision? It’s like asking a baseball player why he decided to swing the bat at a particular pitch: the velocity of the game makes thought impossible. Brady can afford to give each receiver only a split second of attention before he has to move on to the next. As soon as he glances at a body in motion, he must immediately decide if that body will be open a few seconds in the future. As a result, a quarterback is forced to evaluate each of his passing alternatives without knowing how he’s evaluating them. Brady chooses a target without understanding why exactly he’s settled on that target. Did he pass to Troy Brown with twenty-nine seconds remaining in the Super Bowl because the middle linebacker had ceded too much space, or because the cornerbacks were following the other receivers downfield and leaving a small gap in the center of the field? Or did Brady settle on Brown because all the other passing options were tightly covered, and he knew that he needed a long completion? The quarterback can’t answer these questions. It’s as if his mind is making decisions without him. Even quarterbacks are mystified by their talents. "I don’t know how I know where to pass," Brady says. "There are no firm rules. You just feel like you’re going to the right place . . . And that’s where I throw it."