Spot the difference: Sophie Duncan shows how we recognise words before colours

21st March 2003 at 00:00
This activity is fun to do with children and adults, which makes it great for pupils to run on school science evenings.

Before you start you need to make two sets of at least 15 cards. On the cards in the first set use several different coloured pens - one for each card - to write the name of the colour you have used. For example, write "red" with a red pen. You can repeat the colours if necessary.

On the cards in the second set write the names of colours that are not the colour of the pen. For example, write "red" with a green pen, and "blue" with a black pen. Ask the children how quickly they can tell you the colours of the words on the first set of cards. Make a note of this on a score sheet.

Using a stopwatch, ask a pupil to time how long it takes for the children to tell you the colours of all the words in the first set. Record this on the score sheet.

Now ask them how long they think it will take to tell you the colours of the words on the second set of cards. Repeat the experiment and write the time on the score sheet.

You should find that it takes longer for them to tell you the colours of the words when there is a mismatch between the colour and the word.

Depending on the age of the children you may find variations in the time differential.

You could try the experiment with younger children who haven't learned to read, or you could split the class into small teams and compare results.

The effect you are measuring is called the "Stroop Effect", named after John Ridley Stroop, who first noticed the effect in the 1930s. It seems to stem from our ability to recognise words being quicker than our ability to recognise colours. There is a mismatch in the information our brain receives that causes us to stumble over the words.

Sophie Duncan is project manager for science at the BBC

Log-in as an existing print or digital subscriber

Forgotten your subscriber ID?


To access this content and the full TES archive, subscribe now.

View subscriber offers


Get TES online and delivered to your door – for less than the price of a coffee

Save 33% off the cover price with this great subscription offer. Every copy delivered to your door by first-class post, plus full access to TES online and the TES app for just £1.90 per week.
Subscribers also enjoy a range of fantastic offers and benefits worth over £270:

  • Discounts off TES Institute courses
  • Access over 200,000 articles in the TES online archive
  • Free Tastecard membership worth £79.99
  • Discounts with Zipcar,, Virgin Wines and other partners
Order your low-cost subscription today