Figure 1.

Stimuli and design. A, Spectrograms of one exemplar of each of the 9 speech conditions. Stimuli consisted of three vowels (/a/, /i/, /u/) pronounced by three speakers (sp1:boy, sp2:girl, sp3:male). B, F1/F2 formant values for all stimuli (2 utterances per vowel for each speaker) and mean ± SD fundamental frequency (F0) values for each of the three speakers. C, Schematic overview of an experimental trial and the fMRI stimulation protocol including a black-and-white version of the ‘boy’ decision picture. Decision pictures consisted of cartoons of a boy, a girl or a man (speaker task), or the letter combinations ‘aa’, ‘ie’ and ‘oe’, corresponding to the pronunciation of the 3 Dutch vowels (vowel task).