**A:** Eye-movement reliability as a function of scramble duration for individual observers. Circles, covariances between the unscrambled eye-movement time courses from a single observer for each scramble duration, and median eye movements across observers for the intact movie. Filled and open circles, covariances for horizontal and vertical eye movements, respectively. a.u., arbitrary units. Gray curves, best fit of the model. The median eye-movement time course for the intact movie was used as a proxy for the “point-of-interest” trajectory in the model (see ). The three free parameters were: *λ*, probability of locking onto the point-of-interest on each fixation after a saccade; *Q*_{H} and *Q*_{V}, the asymptotic covariances for horizontal and vertical eye movements. **B:** Eye-movement reliability averaged across observers (*n* = 10). Filled and open circles, average covariances for horizontal and vertical eye-movements, respectively (replotted from , large symbols). Error bars, SEM across observers. Model was fit to each individual observer and individual fits were averaged. Gray curves, mean fit. Light gray shaded area, confidence interval on the mean fit, computed by taking the standard error across individual fits. **C:** Best fitting value of the parameter *λ*, which corresponded to the probability that each fixation locked onto a point-of-interest. Error bars, 95% confidence intervals obtained through bootstrapping (see Methods).

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