Figure 3. Experiment 1: at the acoustical level, speaker identity is strongly related to vocal tract features.

Upper panels: for every 2-dimensional acoustical space, we measured the classification accuracy as the percentage of imitations that are located farther from the target than the highest ranked caricatures (marked with + and * in Fig. 1) (left). We summarize these results for both targets T₁ and T₂ in a histogram showing the number of acoustical spaces as a function of their classifying performances (right). Lower panels: organization of the targets and imitations in the 2-dimensional space (F₅, disp(F₅ − F₄)), where the highest ranked caricatures of experiment 1 are closer to the corresponding target than the rest of the files for both T₁ and T₂.