Figure 1.

Stroop task. Three examples of each of the three categories of the colour-word Stroop task stimulus: ‘C’ congruent: colour of upper word agrees with its meaning, ‘I’ incongruent: colour of upper word differs from its meaning, and ‘N’ neutral: the upper coloured line does not contain a word (XXXX). The task was to answer ‘Does the colour of the upper word agree with the meaning of the lower word?’ and press one of two buttons for “yes” or “no”. The correct response is indicated by Y or N at the right hand side of each example.