Stimulus-reaction complexity and magnitude of the Stroop effect  

Barać D., Šunjić M.
First author's affiliation: University of Mostar, Philosophy faculty, Psychology department, Mostar, BiH

The aim of the study was to examine reaction times in different situations of the Stroop effect. Thirty subjects participated in various (non)congruent stimulus situations, where they had to react in compatible and incompatible way. Four different words (red, blue, green, and yellow) were used together with four corresponding colours. The word was combined with colours in such a way that six of them made congruent situations and 18 of them made incongruent situations. The subject’s task was, when the word which meant one of the four colours appeared on the screen, to press the adequate key corresponding to the colour or the meaning of the word. In compatible situations, the subject had to: (i) react on the meaning of the word by pressing the key with the name of the colour written in black ink, (ii) react on the colour the word was written in (but not the meaning) by pressing the key of the same colour. In non-compatible situations the subject had to: (i) react on the meaning of the word by pressing the key whose colour corresponded to the meaning of the word, (ii) react on the colour the word was written in by pressing the key with the name of the colour written in black ink. The results showed the shortest reaction times in the compatible situations, where words had meaning of the colours they were written in. Reaction times were longer in situations where subjects reacted to the colour whereby the stimulus colour corresponded to the word. Generally speaking, reaction times were significantly longer in non-compatible situations where subjects had to react to the meaning of the word written in a different colour by pressing the adequate coloured key. The longest times were obtained in situations where stimulus word was written in non-adequate colour and subject had to react to the colour by pressing the adequate key with the name of the colour written in black ink. The results therefore showed that the magnitude of the Stroop effect depends on the complexity of reaction between stimulus and response.