Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Breaking Ball Too Good to be True

14.10.2010
Curveballs curve and fastballs go really fast, but new research suggests that no pitcher can make a curveball “break” or a fastball “rise.”

Led by Arthur Shapiro of American University and Zhong-Lin Lu of the University of Southern California, the researchers explain the illusion of the curveball’s break in a publicly available study in the journal PLoS ONE (study available by request or post-embargo at http://dx.plos.org/10.1371/journal.pone.0013296).

The study comes a year after the same group won the prize for best illusion at the Vision Sciences annual meeting with a demonstration of how an object falling in a straight line can seem to change direction (http://illusioncontest.neuralcorrelate.com/2009/the-break-of-the-curveball/).

That demonstration led to debates among baseball fans over the existence of the break in curveballs, breaking balls and sliders.

There is no debate in the researchers’ minds.

“The curveball does curve, but the curve has been measured and shown to be gradual,” Shapiro said. “It’s always going to follow a parabolic path. But from a hitter’s point of view, an approaching ball can appear to break, drop or do a whole range of unusual behaviors.”

A little terminology: to many batters and pitchers, a break is a deviation from the relatively straight path of a fastball. In that sense, all curveballs break.

The authors of the study use the term to describe an apparent sudden drop or other change in trajectory as the ball nears home plate. That, they say, is an illusion.

The PLoS ONE study explains the illusion and relates the perceived size of the break to the shifting of the batter’s eye between central and peripheral vision.

“If the batter takes his eye off the ball by 10 degrees, the size of the break is about one foot,” Lu said.

He explained that batters tend to switch from central to peripheral vision when the ball is about 20 feet away, or two-thirds of the way to home plate. The eye’s peripheral vision lacks the ability to separate the motions of the spinning ball, Lu said. In particular, it gets confused by the combination of the ball’s velocity and spin.

The result is a gap between the ball’s trajectory and the path as perceived by the batter. The gap is small when the batter switches to peripheral vision, but gets larger as the ball travels the last 20 feet to home plate.

As the ball arrives at the plate, the batter switches back to central vision and sees it in a different spot than expected. That perception of an abrupt change is the “break” in the curveball that frustrates batters.

“Depending on how much and when the batter’s eyes shift while tracking the ball, you can actually get a sizable break,” Lu said. “The difference between central and peripheral vision is key to understanding the break of the curveball.”

A similar illusion explains the “rising fastball,” Lu added.

The obvious remedy for a batter, repeated by parents and coaches everywhere, is to “keep your eye on the ball.”

That is easier said than done, according to the authors. As the ball nears home plate, its size in the batter’s field of view spills out of the eye’s central vision.

“Our central vision is very small,” Shapiro said. “It’s the size of the tip of your thumb at arm’s length. When an object falls outside of that region, strange perceptions can occur.”

Lu noted that the spin of the ball tends to draw the eye to the side, making it even harder for the batter to keep the ball in central vision.

“People’s eyes have a natural tendency to follow motion,” Lu explained.

His advice to hitters: “Don’t trust your eyes. Know the limitations of your visual system. This is something that can be trained, probably.”

Lu, Shapiro and their co-authors plan to build a physical device to test the curveball illusion. Their study was carried out with volunteers tracking the movement of a disk on a computer monitor.

To the authors’ knowledge, the PLoS ONE study represents the first attempt to explain the break in the curveball purely as a visual illusion. Others have tried to explain the break as a result of the hitter overestimating the speed of a pitch.

Responding to comments from baseball fans, Lu agreed that on television, pitches filmed from behind home plate appear to break. He called it a “geometric illusion” based on the fact that for the first part of a pitch, the viewer sees little or no vertical drop.

The ball is falling at the same rate throughout the pitch, Lu said, but because the pitcher tosses the ball at a slight upward angle, the first part of the pitch appears more or less flat.

As a result, the drop of the ball near home plate surprises the eye.

For Shapiro and Lu, who have studied visual perception for many years, the PLoS ONE results go beyond baseball.

“Humans constantly shift objects between central and peripheral vision and may encounter effects like the curveball’s break regularly,” the authors wrote. “Peripheral vision’s inability to separate different visual signals may have far-reaching implications in understanding human visual perception and functional vision in daily life.”

Lu, a professor of psychology and biomedical engineering at USC, holds the William M. Keck Chair in Cognitive Neuroscience. In addition to first author Shapiro, the co-authors were Chang-Bing Huang of USC, Emily Knight of the Mayo Clinic and Robert Ennis of the SUNY College of Optometry.

To read a LiveScience interview with Lu from last year, go to http://www.livescience.com/culture/091102-sl-lu.html

The research was partially supported by the National Eye Institute.

HOW THE EXPERIMENT WAS CONDUCTED:

The authors estimated the magnitude of the illusion by measuring the physical angle of descent that created the perception of vertical descent. As the experimenter adjusted the physical angle of descent, the observer reported whether he/she perceived the disk to fall vertically. For example, the experimenter adjusted the global motion direction of the disk 20 degrees to the right if the observer reported, "No. The disk is moving to the left about 20 degrees." The amount of adjustment became smaller as the observer reported that he/she saw the disk falling closer to vertical.

The stimulus was on until the observer made a response. In response to the observer’s comments, the experimenter changed the direction of the descending disk. The size of the illusion was measured as the angle in degrees between the direction perceived as vertical by the observer, and a true vertical line. There were twenty-four different conditions based on every combination of the following: three eccentricities (0, 15 and 30 degrees), two directions for the internal grating (0 and 180 degrees), and four moving speeds (6.7, 10, 13.3 and 20 deg/sec). Each condition was repeated four times and observers practiced two trials for each condition before data collection.

LU.CURVEBALL.PLOSONE.CM --USC-- OCT. 12, 2010

Carl Marziali | Newswise Science News
Further information:
http://www.usc.edu

More articles from Studies and Analyses:

nachricht Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland

nachricht Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>