Article Figures & Data
Figures
- Figure 1.
A, Timeline of a single trial. Black lines represent the visible (solid lines) and invisible (dashed lines) parts of the target trajectory. Observers received visual feedback of their finger position (right, red dot) and target position at time of interception (black dot). Red dashed line illustrates the trajectory that best fit the interception position. B, Illustration of hypotheses. Dashed diagonal indicates veridical speed judgments. For short visual presentation durations (high visual uncertainty), we expect a strong regression in estimated speed toward the mean physical target speed (center bias). In addition, we expect that sound volume induces a systematic bias in observers’ speed estimates (slower for quiet sounds, faster for loud sounds). Conversely, for long visual presentation durations, we expect less regression toward the mean and only a weak sound-induced bias, indicating that observers relied almost entirely on visual information to estimate target trajectories. C, The five presented ball trajectories defined by different initial launch speeds (gray lines). Vertical line illustrates the border of the hit zone.
- Figure 2.
A, Example of a hand position trace (green). Black line represents the 2D target position, and the red cross indicates the interception position. B, C, Mean individual observer 2D interception positions for the 100 ms (B) and 300 ms (C) visual presentation durations. Each data point indicates one observer’s mean interception position per each of the five target speeds.
- Figure 3.
A, B, Box plots of estimated target speed (n = 16) as a function of physical target speed. Colors denote sound volume conditions, and dashed lines indicate veridical estimates. A, 100 ms condition; B, 300 ms condition. C, Effect of sound volume on the bias in estimated speed averaged across physical target speeds, separately for the 100 ms (filled circles) and 300 ms (open circles) condition. Circles and error bars denote the mean ± 1 within-subject standard error of the mean (SEM); significant post hoc comparisons, *p < 0.05).
- Figure 4.
A, Two-dimensional eye position traces of two representative trials. Bright blue segments indicate smooth pursuit, continuous tracking of moving targets with the eyes, and dark blue segments indicate saccades. Solid and dashed black lines represent the visible and invisible portions of the target trajectory. The shaded area represents the hit zone. B, Effect of sound volume on estimated speed based on final eye position. C, Histogram of trial-by-trial correlation coefficients from all observers. Black line indicates mean across observers. D, Trial-by-trial correlation of one representative observer.
- Figure 5.
Saccade analyses. A, Effect of sound volume on horizontal and vertical saccade amplitudes for the first catch-up saccade after target onset. B, Vertical saccade amplitudes averaged across physical target speeds. C, D, Cumulative saccade amplitudes of all subsequent saccades. Circles and error bars show means ± 1 within-subject SEM; significant post hoc comparisons, *p < 0.05. Note different scales between top and bottom panels.
- Figure 6.
Bias in estimated speed split separately for the first and second half of the experiment. Solid lines and filled circles represent 100 ms, and dashed lines and open circles represent the 300 ms condition. Circles and error bars show mean ± 1 within-subject SEM.
In this issue
