Saccadic suppression in hockey

i-97c2b37e5a127016255e13eb6c0b4619-friday-partVII.jpgSince yesterday I talked about blinking I figured that today I would re-post something from the old blog about another important eye movement that impacts our day to day life as much or more than blinking - The Saccade. Without further ado, here's the old post (with some edits including a definition of a saccade):

So as per my usual laziness I'm not even going to read the source article and make wide sweeping generalization about the conclusions presented in this news article (which may very well ignore whats in the actual journal article).
I think this stuff is actually pretty cool - there are a number of technical limitations which this group has overcome to 'watch' the eyes of athletes. Short of taking performance enhancing drugs there seem to be fewer and fewer ways of swelling the bodies of athletes - so it has become obvious that scientists of the mind may be playing a larger and larger role in sports performance.

In any case... onto a very obvious conclusion that hopefully the journal authors didn't miss but this story obviously did....actually I'll let you read the snippit of research before I tell you what 'actually' is happening. haha...

Simply put, they found that goalies should keep their eyes on the puck. In an article to be published in the journal Human Movement Science, Panchuk and Vickers discovered that the best goaltenders rest their gaze directly on the puck and shooter's stick almost a full second before the shot is released. When they do that they make the save over 75 per cent of the time.

"Looking at the puck seems fairly obvious," Panchuk said, "until you look at the eye movements of novice goaltenders, who scatter their gaze all over the place and have a much lower save percentage than the elite goalies."

"Goalies often focus on physical things like improving technique but they over-look the decision-making -- the cognitive side of things," Panchuk said. "I think this study shows that you also need to focus on your decision-making and your thinking processes. Having optimal focus is just as important as being in optimal physical shape."

Panchuk plans to continue the study by moving from wrist shots to slap-shots and penalty shots, where the goalie has even less time to react and make a save.

So... I admit it has to be really important that goalies or baseball players know what to look at - obviously - but the largest problem here with novice goal tenders is that they are simply moving their eyes around too much. And what happens when we blink or saccade? yes! suppression of vision! So imagine that during the 1 second a puck is coming toward you 1 eye movement is made - you've lost lets say 200ms of vision.
Now imagine you are a new goalie and you're looking everywhere and you make 4 eye-movements in the second a hockey puck is flying at you over a hundred miles an hour. You are now processing its trajectory for not 800ms but closer to 200ms! That hockey puck is gonna sneak up on you real quick - especially considering saccading messes around with your perception of time as well.

If you'd like a good paper that shows something similar in a different paradigm... here ya go :)
Boot, W.R., Kramer, A.F., Becic, E., Wiegmann, D.A., & Kubose, T. (in press). Detecting transient changes in dynamic displays: The more you look, the less you see. Human Factors.

Read the ScienceDaily article here

Do you not know what a saccade is? Here's a good explanation from wikipedia:

In regard to the eye, saccades are quick, simultaneous movements of both eyes in the same direction [1]. Initiated by the frontal lobe of the brain (Brodmann area 8), saccades serve as a mechanism for fixation, refixation, rapid eye movements and the fast phase of optokinetic nystagmus [1].

Humans and other animals do not look at a scene in a steady way. Instead, the eyes move around, locating interesting parts of the scene and building up a mental 'map' corresponding to the scene. One reason for saccades of the human eye is that only the central part of the retina, the fovea, has a high concentration of color sensitive photoreceptor cells called cone cells. The rest of the retina is mainly made up of monochrome photoreceptor cell called rod cells, which are especially good for motion detection. Consequently, the fovea makes up the high-resolution central part the of human retina.

By moving the eye so that small parts of a scene can be sensed with greater resolution, body resources can be used more efficiently.

The dynamics of saccadic eye motion give insight into the complexity of the mechanism that controls the motion of the eye. The saccade is the fastest movement of an external part of the human body. The peak angular speed of the eye during a saccade reaches up to 1000 degrees per second. Saccades last from about 20 to 200 milliseconds.


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"So as per my usual laziness I'm not even going to read the source article and make wide sweeping generalization about the conclusions presented in this news article"

At least you're honest. I do this all the time.

I played hockey as a kid (obligatory in New Hampshire) and was a goalie (my hero was Ken Dryden) and as I got older, and the fucking kids kept firing the puck harder, I started wondering what separated the schlubs from the Grant Fuhrs.

I decided these guys must be able to translate the visual input we all have into a crucial fraction of a second that resulted in their being able to put the pad/mask in the right place. Plus a bit of being fearless; I never saw a shot that went over ~80 mph, much less 135 or whatever the nuttyfuck velocity Brett Hull types bring.

In short, I don't think it's sensory.