Fig. 1.

Experimental setup. Forty-nine Klinefelter syndrome (KS) males and forty-nine Controls (C) participated in the experiment, see rightmost columns. Participants responded with a button press using their index finger if the color of the letters (for visual stimuli) was green or if a voice said “green” (auditory stimuli) and responded with their middle finger if the color was red or if a voice said “red”. In the case of a yellow visual or “yellow” auditory stimulus, the participants were instructed not to respond. Stimuli could be highly frequent or less frequent. Participants within the contrasted KS and C groups were randomly attributed to two stimulus groups that counterbalanced color and frequency. Participants thus received a total number of 400 stimuli divided into eight types: Visual Stroop/Low Frequency (VS/LF); Visual Stroop/High Frequency (VS/HF); Visual Non-Stroop/Low Frequency (VNS/LF); Visual Non-Stroop/High Frequency (VNS/HF); Visual Non-Stroop/No Response; Auditory Non-Stroop/Low Frequency (ANS/LF); Auditory Non-Stroop/High Frequency (ANS/LF); Auditory Non-Stroop/No Response (ANS/NR).