Psychometric functions.

<p>(<b>a</b>) Psychophysical data points for “proportion of later responses” are shown for the presentation time and object diameters <i>big</i> (triangle symbols) and <i>small</i> (circle symbols), respectively. Each sigmoid curve represents a fit of a Gaussian cumulative density function (“GCDF” with mean and standard deviation ) to the data points of the respective object diameter. The GCDF-fits approximate the underlying psychometric functions, with the mean indicating the time point of subjective simultaneity. (<b>b</b>) The curves show how and depend on presentation time and object diameter. Each point represents the result of a GCDF-fit to the psychophysical data. If subjects responded correctly, the point of subjective simultaneity would coincide with ( is indicated by the dashed horizontal line).