Psychophysics results from Experiments 1 and 2.

<p>Average change detection performance (<i>d</i>′) across subjects is shown by stimulus condition. Error bars indicate 95% bootstrap confidence interval across subjects. a) In Experiment 1 (<i>N</i> = 10), melody entropy changed with different degrees (Δ<i>β</i>, abscissa) and in both INCR and DECR direction (color). Detection performance increased with Δ<i>β</i> but did not differ by direction, although there was a weak interaction between Δ<i>β</i> and direction due to FAs only (see <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1006162#pcbi.1006162.s007" target="_blank">S1 Fig</a>). b) In Experiment 2 (<i>N</i> = 10), an additional factor of melody length was introduced (color). Detection performance increased with both Δ<i>β</i> and melody length.