The Stroop Effect - Mind Games or an Illusion?
What is the Stroop effect?
The ‘Stroop effect’ was named after John Ridley Stroop who discovered this occurrence in the 1930s. He was born in Murfreesboro, Tennessee, March 21, 1897 and completed his training at Peabody College where he received his Ph.D. degrees. 
Stroop created three classic experimental research theories, while conducting his experiments with a group of participants. His first theory compared reading a list of words in black ink with reading the same list of words printed in different colours. The results showed that there was little or no difference in the time it took to read from both lists. 
He then compared the naming of colours for a list of solid colour squares with the naming of colours for a list of words printed in different colours. His participants took longer to name ink colours of different words. 
His experiments showed that the action of reading was automatic for most people. He demonstrated that when the brain was instructed to do the opposite and pay more attention to the colour of a word it struggled. His participants had to intentionally adjust their responses to complete the new task, as it is not as familiar to us as reading is. This phenomenon is called 'interference'. 
His experimental results showed that people are more practiced at word reading than naming colours, there is less interference with word reading than there is with naming colours. As learnt experiences become part of our memory, it teaches us over time that the meaning of words holds greater significance than the colours they are written in.   
Research shows that the ‘Stroop effect’ affects most people who try to identify words quicker than colours. 
Test Yourself: Stroop effect 
Like most people across the globe, there is a tendency to read the words rather than say the colours that they are in.  If you are feeling somewhat confused, you have just experienced ‘interference’. 
Is your mind playing tricks on you?
National Geograhic Images 
Have you ever asked yourself the question, how do words and colour influence what we see and what our brain processes?
And if what we see the brain believes, well how does the brain cope with such a mix of information?
Let's try this simple experiment to help you understand what is happening in your mind and thought process.
Try your best not to read the words, but make yourself say the colours that they are written in!
American Psychological Association
So how was your first attempt? Was it better or worse than you expected?
As you can see from the above example if the word red is printed in blue, most people will read what the word says, while it is usually more difficult to read out the colours of the text instead.  Amazing isn’t it!
J. Ridley Stroop conducted this same experiment on his participants. The experiments he conducted tested the way in which individuals focussed there attention. This phenomenon is nicknamed the ‘Stroop effect’.  Simply put, the Stroop effect shows how the brain processes words and colours differently.
How does the Stroop Effect Work?
The uses of words on there own have a much stronger influence over a person’s ability to say the colour. The interference that occurs between the different information received by the brain causes a conflict to occur. This happens because of what the words say and what the colour of the words mean.  
J. Ridley Stroop developed his experimental theories to explain this occurrence:
The first theory was called - Speed of Processing Theory: He showed that the Interference occurs because, people are able to read words much quicker and to name the colour of the word is much more complex. 
The second theory was called - Selective Attention Theory: Interference occurs because; naming the actual colour of the words requires much more attention than reading the words. 
Interference Test: Run Experiment
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So what was your score? Was there a huge difference between the first and the second test? Were you surprised by the result?
What is Interference?
Interference occurs when you look at one of the words, you see both its colour and its meaning. These two different bits of information begin to confuse the brain, which then causes a conflict, forcing you to make a choice.  Our experiences and stored memories has taught us that word meaning is more important than the colour a word is written in. Interference occurs when you try to pay attention only to the colour. The interference that happens suggests that you are not always in control of what you can pay attention to. This interference is called the ‘Stroop Effect’. 
Why does Interference send ‘mixed messages’ to the brain?
Often referred to as Interference theory, this theory focuses on the human memory. Human memory is the process of which we all encode, store and retrieve information.  The brain engages in a complex process which begins with the encoding or registration, receiving, processing and combining of received information or stimuli. That information is stored or becomes a permanent record of information. 
Interference happens when you try to retrieve, or recall information. This involves the brain searching for some recollection of the stored information in response to some prompt for use in a process or activity. 
Interference theory occurs where learnt information, memories or thoughts conflicts with new information or material. Trying to access that information becomes difficult and people often would say “it is just at the tip of my tongue”. This response often is affected by both the speed in which you learn and the performance of memory recall. 
Try this memory test!
Why is the Stroop effect important?
The Stroop effect is used in many clinical and psychological applications. It is often used to compare the brain development of early school age children. It has been found that interference is often present in conditions such as brain damage, dementia, or Attention-Deficit Hyperactivity Disorder (ADHD), alcoholism, addictions such as drugs and gambling.  The effect can also be used to determine the severity of these problems, as well as schizophrenia other common mental disorders which are all currently being researched. 
Check out this clip
Researchers have conducted brain processing using multiple tasks and utilised the Stroop effect method. Research has shown that slowed brain processing can also be tested by manipulating words in other ways. Some Stroop effect tests rotate words, or arrange the letters in a clockwise or counter clockwise arrangement. 
This type of testing highlights whether the brain processes the word patterns or the colours faster, and some Stroop tests have variations that reverse letters or scramble them altogether to gain a much more in depth insight into brain function. 
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