Cognitive Psychology · Simplified
Stroop Interference Laboratory
Name the ink colour, not the word. Your own reaction times are the data.
Practice
Name the ink colour
Six untimed practice trials first, with feedback after each one. Ignore what the word says. Respond to the colour it is printed in.
What this needs. Telling four ink colours apart, and about two minutes. Nothing flashes, nothing animates and no trial is ever timed out: each word stays until you answer.
Practice trial 1 of 6.
Your result
Two effects, not one
The dashed line is your neutral mean. Everything to the right of it is a cost, everything to the left is a benefit, and both are measured from the same baseline.
All the values behind this chart
| Condition | Mean reaction time | Correct trials used | Accuracy |
|---|
Key idea: Without the neutral condition there is one number, the gap between congruent and incongruent, and no way to say what produced it. With it there are two: a cost when the word conflicts with the ink, and a benefit when it agrees. They come from different places, they are not the same size, and reporting only the gap between the two extremes hides both.
One person, one short block, in a browser. Fifteen scored trials per condition is far too few to estimate anyone's reaction time reliably, browser timing adds noise of its own, and a facilitation effect this small often fails to appear in a block this length. A result near zero, or the wrong way round, is a result about the block rather than about you. Nothing here measures anything about your attention or your ability.
The longer version adds two colour sets, two trial mixes so the effect can be moved by changing the context, a table of every block run, a transfer challenge and a fully documented simulated route for anyone who prefers not to respond to colour. It is at Stroop Interference Laboratory in the main collection.