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Simon Task Test
A blue or orange square flashes on the left or right. Answer by the colour — blue means left, orange means right — and ignore where the square appears. When position and colour agree the answer comes quickly; when they clash your brain slows down. Thirty-six trials measure that Simon effect.
0% correct
About the Simon Task Test
The Simon task measures how much an irrelevant spatial feature interferes with a choice. Your task depends only on colour, so the square's position should not matter. Yet responses are reliably faster when the square appears on the side that matches its colour, and slower when it appears on the opposite side.
That slow-down is the Simon effect. It shows that even when you try to ignore location, it is processed automatically and competes with the correct response. Answer with the arrow keys, A and D, or the on-screen buttons. Your average reaction time is split into congruent and incongruent trials so you can see the interference directly.
About
The Simon Task Test measures selective attention and response inhibition by presenting coloured squares on the left or right side of the screen. You must press a key matching the square's colour while ignoring its horizontal position. When the colour and position match (congruent trials), responses are typically faster and more accurate; when they conflict (incongruent trials), the spatial stimulus automatically activates the wrong response, creating the Simon interference effect that the test quantifies.
How your result is scored
The tool records reaction time and accuracy for congruent and incongruent trials separately. Your Simon effect score is the difference in mean reaction time between incongruent and congruent correct responses, expressed in milliseconds; a larger difference indicates stronger automatic spatial interference.
Tips to improve
- Keep your index fingers resting on the two response keys to minimise movement time.
- Focus on the colour word or hue, not the square's location, throughout each block.
- Take a short break if you notice fatigue increasing your error rate.
- Practice a few warm-up trials before starting the scored session.
Related
Frequently asked questions
- What does a high Simon effect score mean?
- A high score shows that irrelevant spatial information strongly interferes with your colour-based response selection, indicating lower inhibitory control in this task.
- Can I use this test to diagnose ADHD?
- No, this is a cognitive screening tool only; it cannot diagnose ADHD or any other condition.
- Why are there practice trials before the real test?
- Practice trials let you learn the colour-key mapping so the scored blocks measure interference, not initial learning.
- Does the test work on mobile devices?
- The test is designed for keyboard input; touchscreen response mapping is not currently supported.