Fig. 2.

Stroop test.

Participants are instructed ignore the text-meaning of the words, and required to respond by button press to the font color only. The presented items can be (a) congruent (‘blue’ printed in ‘blue color’), or (b) incongruent (‘green’ printed in ‘red color’). Usually, when word meaning and printed color are incompatible, i.e. the process called interference, response times will be prolonged (Stroop, 1935). Subjects are instructed to respond as quickly and accurate as possible. Each stimulus remains on the screen until a response is made. An interval ‘+’ appears for 1000 ms between stimuli. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)