The Eureka moment came in 2014. The site was the LSU football complex.

Brandon Ally had just finished a meeting with LSU coaches, where he presented data from the S2 Cognition test he had given to all 109 players on the Tigers roster two weeks earlier. This was the beta run for the test, which Ally and fellow neuroscientist Scott Wylie created to measure how athletes process information and make split-second decisions during competition.

Ally’s reports identified strengths, weaknesses and tendencies for each player based on the test results.

When LSU offensive coordinator Cam Cameron read the information, he stood up and exclaimed to the room: "Holy (expletive), this kind of stuff would have saved me at least 12 months of evaluating players. This is gold."

In an instant, Ally knew: "We’re on to something."

What Ally and Wylie were on was the prototype for cognitive testing of human athletic performance.

Leaning on decades of experience in the field of neuroscience, Ally and Wylie created a system that grades players in several cognitive categories — perception speed, trajectory estimation, rhythm control, timing control, distraction control, impulse control, stopping control and instinctive learning — and quantifies it with a cumulative score based on the aggregate.

A score of 40-60% is considered average. Anything above 80% is elite.

The S2, which has been called "a 40-yard dash for the brain," came to the forefront this NFL offseason after it was cited as a key factor in the San Francisco 49ers’ decision to draft Brock Purdy, the seventh-round sensation out of Iowa State. Purdy reportedly scored in the mid-90s percentile on the S2.

The S2 has become the Holy Grail for sports executives, coaches and scouts: a test that defines traits that were once undefinable — instincts, decision-making, field vision, impulse control.

The S2 is different from the controversial Wonderlic exam and other IQ tests in that it measures "the cognitive way your brain is wired to process information," Ally said. "When we think about intelligence, it is often associated with reasoning ability, or how well a player can intake a playbook, or a very complex system, and understand those things. There are plenty of IQ tests out there, but they don’t tell you anything about how players are going to perform in those split-second timeframes once they have all of that information. That’s the difference."

Today, more than 60 colleges and 45 professional teams in the country’s five major sports leagues use the S2 technology to evaluate personnel and enhance performance — among them LSU and the New Orleans Saints, who were among the company’s first clients.

Indeed, the S2 has deep Louisiana ties.

Ally, the co-founder, is the son of New Orleanians. He moved to Lafayette after his father opened a psychiatric practice there and was a standout track athlete at St. Thomas More. Ally earned a scholarship to run cross country at the University of Tennessee, where he met Tommy Moffitt, then the Volunteers' assistant strength coach.

Ally earned his doctorate in neuropsychology from Southern Miss in 2004 and landed on the faculty of the neuroscience department at Vanderbilt University, where he and Wylie brainstormed the idea for the S2.

When Ally was looking to run a beta test of the system in 2014, he reached out to Moffitt, who had moved on to LSU. Jack Marucci, the director of performance innovation, took it from there and helped integrate the S2 into use for every team in the LSU athletic program, except swimming and track and field.

"I’m passionate about it because I’ve seen the results," Marucci said. "The S2 is the gold standard. It’s given us an edge. It helps players fulfill their potential."

The S2 played a key role in LSU’s 2019 national championship football season. Using S2 data, coaches were able to identify strengths and weaknesses in the visual processing of LSU receivers and integrate this information into their offensive game plans.

One receiver lined up only one side of the field to take advantage of his dominant eye. Others ran only certain routes. The results were dramatic: the receiving corps’ dropped pass totals declined dramatically, and LSU set school records for scoring (48.4 points a game), offense (568.4) and passing offense (401.6).

To this day, the 2019 team’s aggregate score remains one of the highest in the history of the S2. Quarterback Joe Burrow’s total score of 97 broke down into four categories: visual learning (94%); instinctive learning (97%); impulse control (97%); and improvisation (93%). Receiver Justin Jefferson also recorded an elite score, particularly in the area of decision complexities, Marucci said.

"Yes, they were talented," Marucci said. "But their overall intelligence, football savvy and football IQ was off the charts."

LSU, like many schools, not only uses S2 in its selection and recruitment decisions, but also as a developmental tool to enhance performance. The Tigers even use drills created by S2 to help athletes improve their performance on the field and court.

"People don’t understand that if you can improve performance by 2 to 4 percent, it is huge," Ally said. "It is the difference between the 2019 team and not winning a title."

It didn’t take long for Saints assistant general manager Jeff Ireland to learn about the S2 from his contacts at LSU. Shortly after joining the Saints in 2015, he learned about the technology and took it to general manager Mickey Loomis.

Saints officials were intrigued, but they wanted to verify the S2’s authenticity, so they used Drew Brees as something of a cognitive guinea pig to gauge its effectiveness.

"They called me and said we would love to see Drew Brees’ numbers," Marucci said. "If he doesn’t score well, then this thing is a freakin’ farce. Of course, he comes back very elite. He had very similar scores to (Patrick) Mahomes."

Brees recorded a score that ranked “among the top 10 quarterbacks we’ve ever tested here,” Ally said. "In the areas of instinctive learning (identifying subtle clues and 'tells' from a defense) and distraction control (maintaining focus in the midst of chaos), Brees was almost “superhuman,” Ally said.

"In (instinctive learning), Drew is the best athlete we’ve ever tested in 10 years, across 40,000 athletes in nine sports, and that includes the top 10 Halo players in the world, Air Force pilots and video gamers," Ally said.

The Saints and Cowboys were the first NFL teams to use the S2. Ireland has used it as an evaluation tool for draft prospects since 2015 and has championed the S2 to his NFL peers.

"S2 Cognition helps us gain perspective on how quickly and accurately players process information and ultimately make decisions on the field," Ireland said in a testimonial on the company’s website. "We love the guidance that the evaluation and the S2 team gives us with big-time decisions."

The Saints’ famed 2017 draft class, which featured future stars Alvin Kamara, Marshon Lattimore, Ryan Ramczyk and Trey Hendrickson, scored extremely high on the S2, Ally said.

"That 2017 draft was so much fun to be a part of and be around," said Ally, who has been an invited guest to Saints drafts in the past. "We had a small part in that, which was really, really cool."

Saints rookie quarterback Jake Haener was one of 850 prospects tested in the months before the 2023 NFL draft. He said the 45-minute session featured multiple tests on a specially designed gaming laptop and response pad. One test gauged his impulse control with moving color-coded objects. Another tried to determine how many objects he could simultaneously track on the screen at one time.

"It was definitely challenging," said Haener, who reportedly scored in the 96th percentile on the test, which ranked second among quarterbacks in the 2023 NFL draft.

Purdy’s success last season vaulted the S2 into the limelight and had a direct impact on this year’s draft. Six quarterbacks 6-foot-1 or shorter were selected, including Bryce Young at No. 1 overall and Haener, whom the Saints took in the fourth round.

"When you have a mind that is capable of going to elite levels, a brain that is capable of going to elite levels, you will always overachieve expectations. You will always be a better athlete than people give you credit for," Minnesota Vikings quarterback Kirk Cousins said on a recent episode of the S2 podcast.

"And the opposite is true. If you don’t have the brain that is capable of going to elite levels, no matter how fast you are, no matter what your physical traits are, no matter how good you look coming off the bus, you will always under-deliver, because at some point the rubber is going to hit the road and you’re going to be calling on that brain to show up, and (the cognitive ability) is not going to be there."

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