Calculated change in gaze position, l, as a function of time along with resulting variation method plot of N(Δt) in inset for (A) participant Y1, (C) FTD5 viewing the computer-generated fractal image and (E) FTD5 viewing the natural landscape.

Actual data is shown as black circles and surrogate data in red squares. Note time axis in insets have been cropped in order to see details of plot. The associated plot of–log N(Δt) vs. log Δt for (B) the actual and surrogate data for participant Y1, and the data for FTD5, (D) and (F). The linear behavior observed in the actual data demonstrates the scale invariance of l (t) within the measured range. The Hurst exponent H is listed on the plots and was obtained from the slope of the linear fit (slope = 2-H). Insets shows residuals of the linear fits.