Figure 3: Results–Experiment III.

Percent of responses indicating that the target preceded by an upright walker was larger plotted against the difference between target (disc) sizes. Means per condition with fitted psychometric function. Error bars show s.e.m. Asterisks indicate significant difference of PSE at p < 0.01. Data for both ISIs (17 ms, 100 ms) were aggregated for analysis. The functional form of the psychometric function is given by f(x; a, l) = a/(a + exp(−l*x)), and thus the PSE by x = −ln[a]/l with fit parameters a and l. Note that the psychometric function for illustration is a fit to the average data, while for statistical analysis each individual was fitted with a separate psychometric function and analysis was based on the distribution of the individual PSEs.