We interact with our
environment in different ways. 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 recognize that legs are needed on a chair because the
seat needs to be elevated, and without even being aware, we have automatically
processed and understood this information.
When psychologist 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 renowned examples of a psychological
test and is now widely used in clinical practices all over the world. The
Stroop Test 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 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 as far back to works in the nineteenth century
by James McKeen Cattell and Wilhelm Maximilian Wundt.
To conduct his experiments,
Stroop gave participants variations of the same test: The first variation asked
participant to read color words written in the same color ink as the word
(congruent), the second variation asked the participant to name the ink color a
word is written independently of the written word (incongruent) and a third
neutral test in which participants were asked to state the name of the color squares.
All variations of the Stroop Test were timed, and errors recorded. The total
time and number of errors was compiled and studied.
Stroop observed that
participants took a significantly longer time to complete the color reading in
the second variation of the test than they had taken to name the colors of the
squares in the third variation. This delay had not appeared in the first
variation. Such interference was
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 check itself and identify
instead the color of the word (the ink is a color other than red), a process
that is not automated.
Different parts of the brain
are responsible for processing different types of tasks. When a person is shown
the word “RED” in the ink color blue, one part of the brain will be
interpreting 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 conflicting
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 ignore 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.
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
cognitive effort. When there is a conflict between these two sources of
information, our cognitive 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 responses, and makes the task take longer.
a number of theories that attempt to explain why the Stroop Effect happens.
Maybe the brain reads faster than it recognizes color. The brain might 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.
in the original Stroop Test were with normal cognition function across the
adult age range (24 – 81), with differing levels of education. Stroop’s studies
have found that interference does increase with age because the cognitive
capacities required to suppress the more automatic response begin to decline.
However, the findings with regard to gender are more equivocal, with some
studies finding differences and others, not.