The Stroop Test

The Stroop task is among the popular research tools used in experimental psychology. It involves creating a conflict situation using words and colors. The original experiment was conducted by John Ridley Stroop way back in 1935. The participants are asked to do an oral reading of color words – like “red“, “green“, “blue” etc. in these tasks. In his first experiment, Stroop compared the reading times of words in two conditions: a) the neutral condition: words are presented in a normal black ink on a white background; and b) Incongruent condition: having incompatible color combinations e.g. “red“. It was during his second experiment that he found the reading times were much faster when using colored rectangles as compared to incongruent color-word combinations.

Other Stroop paradigms have also compared incongruent with congruent conditions. The Wikipedia article on the subject summarizes their results:

Three experimental findings are recurrently found in Stroop experiments:

  1. A first finding is semantic interference, which states that naming the ink color of neutral stimuli (e.g. when the ink color and word do not interfere with each other) is faster than in incongruent conditions. It is called semantic interference since it is usually accepted that the relationship in meaning between ink color and word is at the root of the interference.
  2. Semantic facilitation, explains the finding that naming the ink of congruent stimuli is faster (e.g. when the ink color and the word match) than when neutral stimuli are present (e.g. when the ink is black, but the word describes a color).
  3. The third finding is that both semantic interference and facilitation disappear when the task consists of reading the word instead of naming the ink. It has been sometimes called Stroop asynchrony, and has been explained by a reduced automatization when naming colors compared to reading words.

I needed a mobile (Yay, HTML5!) Stroop task as one my experiments in a class project. First, I tried using the Google Speech API but it was failing to recognize my own speech inputs, so I resorted to using regular buttons instead. I also wanted to vary the difficulty of the task, so I added an option of adding more color variations (More buttons, more targets, Fitts’ law …). Here’s what I could come up with in a couple of hours: