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A recent episode of CBC's Quirks and Quarks featured a segment on curveballs. Despite a right-off-the-bat gaffe (Bob McDonald equates "breaking ball" with "curve ball"), it's an interesting segment that is unlike anything I've read in the online research community. Wanna hear about it?

The research comes from Dr. Howard Shapiro, a vision scientist and psychologist at American University in Washington D.C.

The basic idea of the research is that batters falsely perceive curveballs as having a "hump". As opposed to a fastball, the straightest pitch, and other types of off-speed pitches, which, although not as straight as fastballs still appear to travel in a fairly straight line, a curveball looks like it takes a precipitous dive at the last second. We're all familiar with the idea, even just from watching TV.

(By the way, a stat I've never seen before: curveballs apparently spin at about 1500 RPM. Obviously now I want to know whose curveball spins the fastest. Get on that, Fangraphs!)

In reality, this isn't the case. A curveball's trajectory is not a straight line, but its parabolic path is much smoother and straighter than batters perceive. The reason they see this sudden change in direction is related to vision - namely, central vs. peripheral vision. A curveball has two important components of motion: it's dropping and spinning. We can perceive both of these motions when we're looking directly at the ball, but when we switch to peripheral vision our brains can't handle them. It tries to combines them, loses some info in processing, and we perceive the ball as traveling at some angle relative to what we see with central vision.

To see this concept in action, check out the demo over at Quirks and Quarks' website.

"So", you say, "just keep your eye on the ball!" It's a good point! Why bother using your peripheral vision if it's just going to screw everything up? Unfortunately, it's unavoidable. As the ball gets closer and closer to the plate, the batter starts to perceive it with both central and peripheral vision simply because of its proximity.

In addition to that, batters don't, in fact, keep their eye on the ball. About halfway through a 0.6s pitch the batter's eye shifts from where the ball is to where he thinks it will be as it crosses the plate, so he can get his swing ready. This means, of course, he's only using peripheral vision to see the ball, and it's at this precise moment, when the ball's perceived trajectory abruptly shifts, that the batter sees a "hump". Shapiro claims that this last 0.3s in which the batter is perceiving a skewed trajectory results in an approximately 1-foot discrepancy between the ball's actual and observed location as it crosses the strike zone. Obviously batters have figured this out, so there's a great deal of guesswork involved in hitting a curveball. But even those who are great at it would admit that the less guesswork, the better.

Okay, so can batters learn anything from this? First, if they're able to track the ball for a longer period of time before switching to peripheral vision, the magnitude of the perceived break would be diminished. Second, says Shapiro, "practice makes perfect". It may seem like generic and obvious advice; obviously batters practice hitting curveballs all the time. It's a pretty important skill. He didn't really elaborate on this point, but I think the idea is that batters may be practicing the wrong things. Instead of practicing predicting the end location of a curveball, perhaps batters should be practicing letting it travel farther before taking their eye off the ball because of the diminished perceived break, even if it means leaving the batter with less time to get his swing ready.

"Dr. Shapiro, thank you very much!" No, thank YOU, Bob McDonald!
The Science of Curveballs | 26 comments | Create New Account
The following comments are owned by whomever posted them. This site is not responsible for what they say.
Mick Doherty - Monday, November 29 2010 @ 11:05 AM EST (#226366) #

(Bob McDonald equates "breaking ball" with "curve ball")

Not exactly -- the transcript reads,
" ... a good breaking ball, which can be either a curveball or fastball that suddenly drops, rises or changes direction as it nears the batter."

That's not exactly accurate, but it's a pretty decent summation for the basebally dumguy who doesn't know a double from a double play. And besides, a curveball IS a type of breaking ball!

Good, interesting link, though ...

Mike Green - Monday, November 29 2010 @ 11:13 AM EST (#226367) #
Not exactly accurate?  A fastball that rises is a "breaking ball"?...Say it's a trick, Mick!
Mick Doherty - Monday, November 29 2010 @ 11:39 AM EST (#226368) #
Agreed, I think the use of "fastball" there is what makes it most not-accurate. If it said "or a pitch that ..." it'd still be sligbtly off, but it'd be righter., you know?
Greg - Monday, November 29 2010 @ 12:32 PM EST (#226369) #

Mike Stadler's "The Psychology of Baseball" talks about a similar dynamic of fastballs.  How for the last stretch of the ball's path before it gets to the plate the ball is actually moving faster than the human eye can see, so players are actually mentally estimating the path of the ball and projecting that into their vision as reality.  Which is where rising fastballs come from...if this estimation is wrong the ball will suddenly appear higher than where the batter's eye was telling him it was.

It actually came up in a philosophy class last week, apparently it is a prime example of Husserl's phenomenology of retention (I may be butchering this, although I'm taking a class on philosophy I'm barely following that's going on).  We don't experience everything in a subject-object relationship, but some kind of a three way subject - projection of an object in our minds - object relationship.  It took a little explaining as the class in question is in England, so no one is familiar with baseball...but I'm always excited when I can combine baseball and academia. 

Chuck - Monday, November 29 2010 @ 01:11 PM EST (#226371) #

I believe it was Robert Adair (the Physics of Baseball dude) who long ago debunked the idea of pitches "falling off the table", informing we lay folk that breaking balls actually follow a parabolic path. I imagine that many broadcasters who speak of this phenomenon truly believe it to be real and not merely the result of faulty perception.

And to Greg's comment, the segue into philosphical discussions of phenomenology are fascinating. Click on the Reversal button at the site linked to by Dave and you quickly see how the "I know what I saw" defense is as airtight as Swiss cheese.

perlhack - Monday, November 29 2010 @ 01:44 PM EST (#226373) #'s an interesting segment that is unlike anything I've read in the online research community...

Are you sure such a story hasn't been previously posted to Batter's Box? I'm just askin' ...
Mike Green - Monday, November 29 2010 @ 08:22 PM EST (#226388) #
This discussion raised a question for me.  What about vision correction, i.e. glasses or surgery, and the interaction between peripheral and straight vision necessary to hit a curveball?  It is definitely different wearing glasses, although Rance Mulliniks (and others) have made the adaptation pretty well.  My thoughts also turned to the possibility of surgical vision correction leading to "better than new" transitions between peripheral and straight vision.  There is no highly paid sport in which superior vision is so prized.
rpriske - Tuesday, November 30 2010 @ 08:32 AM EST (#226396) #

I heard that show and he DID mix up the 'breaking ball' 'curve ball' thing right in the opener.

He said something like "there are pitches such as the fast ball, slider and knuckleball, but we are talking about the curve ball, also known as the breaking ball"

There was another breaking ball right in his list of 'other' pitches!

(but yes, it was an interesting bit... but not new. This was broadcast during the World Series)

cybercavalier - Tuesday, November 30 2010 @ 10:35 AM EST (#226398) #
Sorry for a bit off-topic.

Referring to free agent signing, is the Jays interested to sign or rumored to be negotiate for the following players?
1) Jesse Crain the Torontonian from the Twins
2) 1B/DH Nick Johnson from the Yankess, whose on-base ability shall help the Jays offense and help the current void at 1B should Lind penciled to be the future 1B.

Thank you

stevieboy22 - Tuesday, November 30 2010 @ 11:30 AM EST (#226400) #
1B/DH Nick Johnson from the Yankess, whose on-base ability shall help the Jays offense and help the current void at 1B should Lind penciled to be the future 1B.

Is this a rumour or your speculation? I'm interested because I have always liked Nick Johnson.
Chuck - Tuesday, November 30 2010 @ 11:56 AM EST (#226401) #

1B/DH Nick Johnson from the Yankess, whose on-base ability shall help the Jays offense

You mean for the 100 at-bats he'd be healthy for.

Oxygen8 - Tuesday, November 30 2010 @ 01:29 PM EST (#226403) #
an incentive laden contract based on AB's wouldn't hurt, even if nick johnson is!

also, i like the idea of a one year stop gap type guy at 1st base/DH this year. there are going to be some mighty fine 1st basemen available next year.

the yankees have tex, and boston wants a-gone. if beeston is telling the truth about spending big money on the right guy (that means albert pujols), the jays could actually pull this off.
Parker - Tuesday, November 30 2010 @ 02:08 PM EST (#226405) #

1B/DH Nick Johnson from the Yankess, whose on-base ability shall help the Jays offense

You mean for the 100 at-bats he'd be healthy for.

No kidding.  I like Johnson when he's healthy, but he's never healthy.  The team would get more production out of bringing back Lyle Overbay, who is a very similar player if you knock a few points off his OBP but doesn't have the durability issues.

92-93 - Tuesday, November 30 2010 @ 02:48 PM EST (#226407) #
Overbay's OBP his last 4 seasons is .344; Johnson's is .423. Obviously you can't sign him expecting him to be your everyday 1B but the difference between Nick & Lyle isn't merely a few points of OBP. The Blue Jays needs Johnson's upside more than Overbay's reliability.
Chuck - Tuesday, November 30 2010 @ 02:57 PM EST (#226408) #

an incentive laden contract based on AB's wouldn't hurt, even if nick johnson is!

Even with an incentive-laden deal, Nick Johnson presents problems because of his brittleness.

When he gets hurt, you could basically lose him for the season, which means you need a serious plan B. The Yankees went into last season thinking a healthy Nick Johnson would be a bonus, but they had contingencies in place to backfill his potentially foregone AB at DH. Any team that does not have such contingencies in place would probably have no interest in him.

If Lind were plan B to take over for Nick Johnson at 1B, say, why not just go ahead and make him the first baseman in the first place, since he would likely end up taking over anyway. Why let the inevitable injury to Johnson force you into your plan B moves?

Mike Green - Tuesday, November 30 2010 @ 03:18 PM EST (#226409) #
At this point, Johnson's upside is pretty limited.  He had old player skills from the time he arrived, and his power seems to have taken a hit as he crossed 30 and reminds me quite a bit of Randy Milligan. 
China fan - Tuesday, November 30 2010 @ 03:35 PM EST (#226410) #
Some interesting news is breaking now on the Jays minor-league coaching appointments.  Sal Fasano gets promoted to New Hampshire as their manager.  Mike Redmond, who was in the majors last season as a catcher for Cleveland and is just 39, becomes the manager at Lansing.   Rick Langford becomes the Pitching Rehab Coordinator.  And, most intriguingly, the Jays have hired Marty Brown, a veteran of playing and coaching in Japan, to take over as manager at Las Vegas.  He has managed Japanese teams for the past five years, and also has three years of playing experience in Japan.  Does this finally signal that the Blue Jays will begin to hunt for playing talent in Asia?  If so, it would be long overdue.
Chuck - Tuesday, November 30 2010 @ 03:36 PM EST (#226411) #
Johnson seems to have morphed from a guy who would take a walk to a guy who's looking to walk. Definite old guy skills.
jgadfly - Tuesday, November 30 2010 @ 05:17 PM EST (#226418) #
Sal Fasano gets promoted to New Hampshire as their manager ...  Great promotion !   The greatest beneficiary will be Travis d'Arnaud who will now have a fairly competent in-house catching mentor just a few steps away .   Hopefully d'Arnaud will be sufficiently recovered from his August back surgery to take full advantage of this opportunity .
cybercavalier - Tuesday, November 30 2010 @ 06:53 PM EST (#226421) #
First of all, thank you for the quality feedbacks.

Frankly, the Crain and Johnson transactions are speculations. When Overbay was almost to be let go and Lind was rumored to take over 1B and given Brett Wallace and Dopirak are gone, Nick Johnson seems to fit the bill. Johnson and Lind could split time at LF, 1B and DH. Lind was penciled to be the 1B in plan A, which is a balance of Jays resources on batters, especially with the arrival of Rajai Davis. Johnson seems to be that 1-year contract guy who can help the Jays, just like Kevin Gregg of last season.

christaylor - Wednesday, December 01 2010 @ 12:31 AM EST (#226444) #
Not to pour cold water on this stuff but 1) I doubt the population used in this experiment can tell us anything about MLB players 2) even worse, in MLB hitters must make the the decision to swing well before the illusion would kick in

Full disclosure: I haven't read the paper in its current form but was, last May, at the conference where this work was presented before publication... so hopefully the concerns that I heard kicking around about the scientific content itself were addressed, but to say this has anything to with what hitters in MLB do is a stretch.

I'm not even going to mention that the author who presented this paper at the conference hadn't even heard of Sandy Koufax until the day of his talk. Oops. Just did.

That being said, if the authors can get an MLB team interested in this... more power to them. If through this I can get any MLB team interested in the work I've done on how the visual system ages... I'll happily overlook that this illusion has little or nothing to do with an actual curveball (in MLB or not).
Rich - Wednesday, December 01 2010 @ 01:21 PM EST (#226466) #
No thanks to Nick Johnson.  Yes, his career OBP is over .400 and the Jays could use that.  But health is a skill and Johnson doesn't have it.  He's played 100 games once in the past 5 years, not to mention the fact that he's barely slugged .400 during that period.  The Jays don't need another lefty bat with little or no defensive value either.

The hype around NJ is largely based on 2 things: 1 - he was a Yankee prospect and 2 - his OBP in AA was .556 at age 20.  That was in the last century.  As a big league player he has been a huge disappointment and I hope the Jays look elsewhere.  If you're talking about him as a bench player I'd rather have say, Eric Hinske.

92-93 - Wednesday, December 01 2010 @ 01:55 PM EST (#226467) #
He's actually played in 100 games twice in the last 5 years, and if you weren't having fun with arbitrary endpoints it would be 3 times in the last 6. And then if you really want to be honest he's played in 100 games 3 times in the last 5 years, because the 2007 season was missed entirely because of an injury in 2006 and he was never expected to perform that year.

It's also a wee bit disingenuous to label Johnson as another no glove LHB - he hits LHP better than RHP, and hits LH starters even better. A Johnson-Davis combination would be pretty valuable on the bench. Personally I like these old man skills everyone keeps referring to if it means an OBP north of .400. Manny Ramirez is another example of a guy everyone has written off as finished, and he's coming off a .409 OBP (.420 in the short AL stint). This team needs that sort of player badly (or has everyone forgotten what the 2010 Blue Jays looked like already?!).
Rich - Wednesday, December 01 2010 @ 03:19 PM EST (#226474) #
I admit I misread the stats grid I was reviewing, but my point is still valid - Johnson is an unreliable entity.  Talk about disingenuous - you want to discount 2007 in evaluating his reliability?  That's ABSURD.   I picked the last 5 years because that's his most recent track record.  If you want to go back further that's fine but there's no argument  that this is a player a team can count on.

Games played (and I have covered his whole career since you seem to quibble that the last 5 years aren't some kind of reasonable indicator):

2010 - 24
2009 - 133
2008 - 38
2007 - 0
2006 - 147
2005 - 133
2004 - 73
2003 - 96
2002 - 129

He's been in the big leagues full-time since 2002 and in that 9 year span he's played 100 games 4 times.  And when he misses time, it's not like he misses a bit, or even half the year.  He's missed a half-season or more 4 times.

Your point that he hits lefties well is fair.  He may be a decent first baseman but his track record shows he's unlikely to stay healthy enough to play in the field regularly.  It's not just in the batters box that NJ has old man skills.  He can't help the team if he's on the DL.  No thanks.

Mike Green - Wednesday, December 01 2010 @ 03:26 PM EST (#226476) #
I like a .400 OBP as much as anyone.  The point is that it is hard to sustain a walk-heavy .400 OBP with not much power and no speed.  You've basically got to be best-in-the-league at avoiding the K.  There have been first basemen in the past who did it, Ferris Fain and Pete Runnels and Mike Hargrove (to a lesser degree), but unless Johnson either knocks his K rate down to 13% of PA or something or starts hitting homers again, it is a good bet that his OBP next year will be something like .360 or less. 

Would I mind if the club took a flyer on Johnson with the idea that he might be the club's first baseman if healthy and mashing in spring training, and an extra bat on the bench (with a smaller pen) if not?  Of course not.  That's a different thing than anticipating that he'll be a better player than Adam Lind or Lyle Overbay in 2011.

92-93 - Wednesday, December 01 2010 @ 04:32 PM EST (#226482) #
None of the pro-Johnson posts here have anticipated anything of the sort, which is why we don't understand the anti-Johnson crowd. He's a bench player.
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The following comments are owned by whomever posted them. This site is not responsible for what they say.