Dustin Johnson, Justin Thomas, Jordan Spieth headline Tour Championship

Welcome to the Tour Championship, which as it turns out, is also something of an actual tour. Come, explore the various peaks, canyons and plateaus of a golfer's temperament.

At the top of FedEx Cup points list, where all the interest and the bulk of the money lives, is an intriguing assortment of emotional approaches to this oft-maddening game. The extremes among the top five in points range from ultra-unflappable (Dustin Johnson) to fiery (young Jon Rahm). From stoic to volcanic. With all the stops in between (see Jordan Spieth and Justin Thomas).

How these players react to a ball wandering into East Lake's Bermuda rough or the inevitable putt that behaves badly will be significant to the show this week, beginning Thursday. And good for that, for how boring it would be if they were all the same, like so many slices of melba toast.

In their varied ways, all must deal with golf's treacheries.

"Most players have learned that this game is so sensitive to changes in emotion," said sports psychologist Bob Rotella, a most widely quoted and published authority on the golfing mind. "Whether it causes you to change the rhythm of your swing or your stroke or you start hitting the ball a lot further or shorter or change your sequence. Anything like that. You better know what hurts your game and you better learn how to stay calm."

From the outside looking in, the process of coping can be a hoot to watch. And to hear.

Take Spieth, as he offers a soliloquy after each shot, most often condemning an inanimate dimpled object for not doing precisely as he commands. Even on those shots that would leave the weekend golfer giddy. All the world can eavesdrop on his thought bubble.

Why, wire him up, he could put guys like NBC's roving on-course reporter Roger Maltbie out of work. But that's OK by him.

"I think Jordan is fun to watch because of his personality. He's young. I still see a little bit of junior golfer in him, which I like. He's excitable. The passion is obviously there. It's a kick to hear his on-going commentary _ 'Don't bury! Don't this! Don't that!' "

MORE: Jordan Spieth leads FedEx Cup by continuing to give himself chances 

To another member of the on-course broadcasting set, Spieth's good buddy Thomas is a fascination for the way he deals with the competitive pressures.

"I've been blown away by him when we've been able to hear the conversations he and his caddie have, down the stretch at the PGA or down the stretch in Boston a couple weeks ago," said Jim "Bones" Mackay, Phil Mickelson's long-time caddie who recently took up the microphone. He was referencing two of the five tournament's Thomas has won this season.

"He's the most relaxed guy you've seen in those kind of spots. He looks like he should be playing in shorts and a T-shirt with his buddies for $5, and he's out there trying to win a major."

"He has great belief in himself. A very confident young man. And he should be," Maltbie added.

In building a career that has featured at least one PGA Tour victory each of the last 10 years, a 2016 U.S. Open championship and a current No. 1 world ranking, Johnson also has built the reputation as one of the least outwardly emotional guys on the course. The face on the coin Johnson uses to mark his ball changes expressions more than he does. From a distance, you start to believe, no matter the mess he's in, that his heartbeat has the slow, constant beat of a dripping faucet.

Hit ball far. Lope athletically and purposefully to next shot. Repeat.

As Johnson sees it, why get all worked up about a game?

"I just don't get angry," he said. "If I hit a bad shot I've already seen it before. It's not like it's something new. I've done it a million times. Why would I be mad about it?"

"For me, it's still a game and we're out here to put on a show for all the fans," he said. "And they don't want to see you pitching a fit, that's for sure."

As the sports psychologist will tell you, those who can operate with that attitude under the harshest conditions are the ones we tend to call champions. 

"You tell guys, look, most of the greatest players in history were pretty darn calm. They didn't over-react to mistakes. They were kind of like (Ben) Hogan _ the Wee Ice Mon _ cool and calm," Rotella said.

Which brings us to the Spaniard Rohm.

He's trying to get a handle on that red mist, which occasionally gathers between his ears when the golf goes bad. You see it in the low boil after a bad shot. You saw it during the U.S. Open as he executed a nice wedge toss with a kicking flourish and had a disagreement with a bunker rake. You await the next eruption, like the crowd gathered expectantly around Old Faithful.

His mental coach is a former bomb disposal expert. Insert pithy aside here. It's just too easy.

Rohm apologized to all for the little snit at the Open and declared shortly afterward that he has "been working a lot on mindfulness _ being aware of the moment, and trying to focus on right now."

As Maltbie sees it, he is simply another player requiring work on an element of his game. Just as Johnson fine-tuned his short game, he said, so does Rahm need to go to work on his short fuse. "I admire Jon for realizing this is a weakness," Maltbie said.

He looks 30, but is just 22, so there is time for Rahm to refine his playing personality.

But what, you ask, if that is just Rohm's basic nature? What if that fire is as much a part of him as his blood type?

"People love to say, 'That's my nature.' I don't care if that's your nature or not if you want to be a great player," Rotella said. "For a guy like Rahm who's obviously a great talent, as the expectations get higher and you start to see what you're capable of, it's easy to start getting really upset when you're not living up to it. That's the challenge, to have really high expectations and stay calm out there. My guess is he wants to be great and he'll learn to control it."

"My whole teaching is that there is no perfect temperament," Rotella said. "There is no personality that has a huge advantage over another personality. It's about learning to be yourself and to play within your personality and use your (beneficial) tendencies and calm down the ones that hurt you."

This week, the focus is solely on the tendencies of just those top few FedEx Cup players as they take on East Lake, the rest of a mere 30-player field and themselves.

This article is written by By Steve Hummer from The Atlanta Journal-Constitution and was legally licensed via the Tribune Content Agency through the NewsCred publisher network. Please direct all licensing questions to legal@newscred.com.