Figure 2.

Analysis of the timing curve. (a) Example of a pecking distribution (expressed as number of pecks per 1 s time bin) across a 15 s delay; average of 21 trials of one individual. (b) Extracting timing parameters by fitting a third-order polynomial function (dash-dotted line) to the pecking distribution (filled circles, as in (a)) including time bins 1–9 s: x-max is the x value of the maximum, indicating accuracy; f(x_max) is the corresponding y value indicating motivation; the grey shaded area under the curve indicates timing precision (extracted from a normalized curve as shown in (c)). (c) Normalized curve “maximum pecking rate = 1” of the same bird as shown in (a, b) (filled circles, dash-dotted line) compared to a bird with lower timing precision (open circles, dashed line; average of 23 trials); the difference in precision (area under the curve) is marked in light grey shading.