To the debate about whether environment or heredity determines personality, Kentucky basketball offers a third intriguing possibility: Position.
Andrew Harrison is the more serious-minded of UK's twins. Their high school coach suggested that might be because he plays point guard, the nerve center of a team.
"He takes more on himself or he feels more pressure because of his role," said Craig Brownson, who coached the Harrisons for Travis High School in Richmond, Texas. "He's always focused on the job at hand. That goes back to the point guard mentality. He takes on that coach-on-the-floor mentality."
Brownson described Andrew as a "little more serious natured." In the high school halls, Aaron was more likely to be joking with friends, he said.
"Where Andrew was more serious," he said. "Not as outgoing, probably. He keeps more to himself, I guess."
Brownson had no idea how Andrew became the point guard and Aaron the shooting guard. It seems like a chicken-or-egg conundrum: Did Andrew's serious nature make him the point guard? Or did the point guard responsibilities make him more serious minded?
The Harrisons were set in their roles by the time they reached high school. "That was kind of their mentality," Brownson said. "Aaron can run the point guard. But Aaron definitely has more of a scorer's mentality."
The twins' father said he had no master plan to make Andrew a point guard and Aaron a shooting guard. He did not decide that Andrew was better suited to be a leader on the floor.
He attributed the reason each brother came to play to one all-knowing source.
"Simply God," Aaron Harrison Sr., said. "God did that. It's what they've always done."A moment later, the elder Harrison noted another factor. When the twins were in the fourth or fifth grade, another player was the point guard. When that player struggled, one of the assistant coaches suggested Andrew get a chance.
"Andrew broke the press and we kept going," the father said.
Even with his relatively carefree personality, Aaron has played point guard, too.
"Aaron always played point guard whenever Andrew went out of the game," the twins' father said. "There's no doubt in my mind he can do that as well as Andrew can."
Aaron proved it in the summer of 2012 when a hamstring injury sidelined Andrew.
But Aaron conceded the point guard position to his brother while claiming to be the superior shooting guard.
"Andrew could dribble a lot better," he said of the brothers' evolution to their positions. "I shot the three before he did."
Andrew suggested the players naturally gravitated to their positions.
"I think it just came naturally," he said. "Aaron was always the scorer and stuff. So I just found ways to get him the ball."
UK Coach John Calipari acknowledges the difficulty in identifying Aaron and Andrew. At Media Day, he noted how Andrew had grown his hair a bit longer. If Andrew gets a haircut, Calipari (playfully?) suggested he might ask Andrew to have the barber shave a line in his head. "So I know who is who," the UK coach said.
To which, Andrew said, "I'm not putting a line. I don't know what he's talking about."
Playing style and approach to basketball might work to identify who's who, the twins' father said.
"Andrew's mentality is he's definitely a pass-first point guard," the elder Harrison said. "Aaron attacks the rim."
Uniform number: 5
Height, weight: 6-6, 215
Hometown: Richmond, Texas.
High school: Travis
Jerry Tipton: (859) 231-3227. Twitter: @JerryTipton. Blog: ukbasketball.bloginky.com.