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Catching a Ball

Catching a Ball. Ayesha Akbar Johanna Loya Sirisha Bhadriraju. Background—Catching a Ball. Michael Land’s hypotheses: Role of eye movements in cricket: to anticipate bounce point Purpose of smooth pursuit

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Catching a Ball

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  1. Catching a Ball Ayesha Akbar Johanna Loya SirishaBhadriraju

  2. Background—Catching a Ball • Michael Land’s hypotheses: • Role of eye movements in cricket: to anticipate bounce point • Purpose of smooth pursuit ** Eyes work to predict movement + move to points revealing greatest and most valuable information • Our own: • Does this apply to simpler activities (catching a ball) and to less skilled participants?

  3. Background—Catching a Ball • Other confirmed Land hypotheses: • All! • Our focus: • Anticipation times • Distance between fixation point during bounce and actual bounce point • Whether or not underhanded, bounce-less throws make a difference in eye movement sequence and frequency

  4. Subject A (Sirisha) • Measured from end saccade to bounce time • Range: 0—268 (high outlier) ms • Mean: 67 ms • Stand error: 34.29 ms

  5. Subject B (Johanna) • Several saccades counted in one “saccade” -> longer times recorded • Range: 0—234 (high outlier) ms • Mean: 66.9 ms • Standard error: 25.39 ms

  6. Conclusions • Other than a couple of high outliers in both subjects’ trials, anticipation was fairly regular • Anticipation of bounce point almost identical between subjects (A: mean 67 msvs. B: mean 66.9 ms) • Corrective saccades usually preceded anticipation times of zero ms. • Corrective saccades more frequent in less skilled participants?

  7. Distance Between Fixation and Bounce Point • Both subjects consistently fixated above the bounce point (likely to predict where the ball will travel next). • Subject A distance: • Range: 3.98—14.44 degrees • Mean: 8.60 degrees • Standard error: 1.49 degrees • Subject B distance: • Range: 3.78—13.30 degrees • Mean: 6.97 degrees • Standard error: 0.98 degrees

  8. Conclusions • Subject A tended to fixate higher above the predicted bounce point than did Subject B. • Subjects fixate above bounce point to predict where ball will travel next • Subject A consistently left more room for error/unexpected ball trajectory

  9. Underhand Throw/No Bounce • Same subjects participated; Subject A recorded • High, underhanded throws • Saccades occurring before and after peak (apex) of throw were counted

  10. Conclusions • High underhand throws generally follow a pattern: • Ball is thrown • Catcher makes between 1-3 saccades to predicted trajectory apex • During ball’s descent (following apex), catcher engages in smooth pursuit until ball is received

  11. Ayesha Akbar Johanna Loya Sirisha Bhadriraju

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