Figure 1.

Pairwise comparison of subspecies in problem-solving performance. (a) Set-ups allowing multiple solving options, $R_{\mathrm{cond}.}^2=0.44$; $R_{\mathrm{marg}.}^2=0.30$; (b) set-ups requiring a specific solving action, $R_{\mathrm{cond}.}^2=0.38$; $R_{\mathrm{marg}.}^2=0.30$.