For us interact with the world, we must understand it. Visual processing is just one of the many ways that we use to understand the world around us. When we see an object, we don’t just see its physical characteristics, we understand it’s uses and purpose in our lives. For example, we see stairs and recognize that they are a means of transportation. Without even being aware, we have processed and understood that they can take you up or they can take you down.
Controlled and automatic processing are two ways in which we process information. Controlled processing involves paying attention and consciously put in effort. Controlled processing is done on purpose while we are aware of what we are doing. In plain English, we have to think about what is going on and make decisive choices. Automatic processing does not need us to pay attention. We also do not have to deliberately put in effort to control automatic processes, it occurs without us giving any thought to it. If we practice something for a long enough time, it becomes automatic. Some examples of automatic processing are breathing and walking.
When John Ridley Stroop asked people to read words on a sheet of paper, he hypothesized that their automatic processing would produce conflicting mental commands. Stroop wanted to discover which command would dominate the thought process in each person and if that dominate process would be the norm for the majority of people. He knew that with further and more detailed testing he could provide the medical community with a breakthrough discovery into brain function. His research technique is one of the most famous and well-known examples of a psychological test and is now widely used in clinical practices all over the world. The Stroop Test is a sets of tests that is normally used to evaluate a person’s mental processing speeds, neuropsychological and cognitive abilities and directed attention skills. It has been instrumental in helping to diagnose different neurological and psychiatric disorders. In recent years, variations have been used to help people increase their mental strength and improve their attention skills.
The Stroop Effect was named after American psychologist, John Ridley Stroop, who published an article in the journal of experimental psychology, in 1935, entitled “Studies of Interference in Serial Verbal Reactions”. He was not the first to publish this occurrence as Eric Rudolf Jaensch published his article in Germany in 1929. The Stroop Effect can be found documented in works by James McKeen Cattell and Wilhelm Maximilian Wundt as far back as the nineteenth century.
To conduct his experiments, Stroop gave participants variations of the same test: The first variation asked the participants to read color words written in the same color ink as the word spelled (congruent), the second variation asked the participants to name the ink color a word is written in, independently of the written word (incongruent) and a third neutral test in which participants were asked to state the name of the color of the squares. All variations of the Stroop Test were timed, and errors recorded. The total time and number of errors were compiled and studied.
Stroop observed that participants took a much longer time to complete the color reading in the second variation of the test than they had taken to name the colors of the in the third variation. This holdup had not appeared in the first variation. Stroop theorized that this could be explained by the automation of reading, where the mind automatically determines the meaning of the word (it reads the word “red” and thinks of the color “red”), and then must intentionally instruct itself to identify instead the color of the word (the ink is a color other than red), a process that is not automatic.
Different parts of the brain oversee the processing of different types of tasks. When a person is shown the word “red” in the ink color blue, one part of the brain will be reading the written word – “red”. At the same time, another part of the brain will be processing the fact that the text is blue in color. This conflict in information causes a delay in the time required by the brain to process the information. To complete the task in the second variation of the test, one part of the brain has to dominate, and at the same time disregard the response of other parts of the brain. This is called interference and normally the part of the brain that handles reading abilities, will dominate.
As habitual readers, we encounter and comprehend words on such a constant basis that the reading occurs effortlessly, where the naming of a color requires more mental effort. When there is a conflict between these two sources of information, our mental load is increased, and our brains have to work harder to resolve the required difference. Performing these tasks (preventing reading, processing word color, and resolving information conflict) ultimately slows down our response time, and makes the task take longer.
There are a number of theories that attempt to explain why the Stroop Effect happens. Maybe the brain reads faster than it recognizes color. The brain may need to focus more to name the color than to read the words. Or simply, after reading becomes a habit, the process of reading is more automatic and effortless than the process of analyzing and naming colors. While differences in theories exist, all basically come to the same agreement that reading is a simpler and more automatic task than stating colors, and that when a conflict between the two occurs, the time needed for processing will increase.
Participants in the original Stroop Test were adults in the age range of 24-81, with normal mental function with differing levels of education. Stroop’s studies have found that interference does increase with age because the mental abilities required to ignore the more automatic response begin to lessen. The findings regarding gender are more unreliable, with some studies finding differences and others, not.