This essay has a total of 1210 words and 7 pages.



The Effect of Visual Field Position and
Type of Stimuli on the Stroop Effect

Reynold Hicks

University of Tampa


An experiment was conducted to test the effect of lateralization and congruency on
reaction time to name colors. This was done using a computer program provided by The
University of Mississippi. This effect is called the stroop effect. Results showed that it
was neither lateralization nor congruency had a significant effect on reaction time, but
the interaction of these two variables that created a significant change in the time
needed to recognize colors. It is believed that this is due to the different hemispheric
functions of the brain. Studies that are similar to this in nature help to better
understand how the brain functions and it capabilities.

The Effect of Visual Field Position and Type of Stimuli on the Stroop Effect

Psychologists have been interested in how the human brain works and how stimuli are
processed and interpreted. The brain is a highly complex organ that is the center for all
our human functions. The more we know about how it works and how efficient the brain is,
the better psychologists will be able to analyze human behavior.

The stoop test has been used for many years to investigate how we process information.
Laterality is one of the factors in which the stroop test can be used to investigate. Many
researchers have examined laterality in the Stroop task. Dyer (1973) showed that
presenting the word and the color separately to the left and right fixation did not alter
the Stroop effect. Interference and facilitation were still factors (MacLeod, 1991). There
are many instances of the left hemisphere showing more interference during this kind of
testing. Aine and Harter (1984) studied this same effect and found that activity
associated with interference occurs in the left hemisphere, effecting the response time
and error-rate measured. Similar results were found in a study conducted by Posner,
Walker, Friedrich, and Rafal; (Citedin, Macleod, 1991) they found that the left parietal
and frontal lobe may be involved in disengaging attention. Many other variables such as
gender, bilingual ness, even handedness have been proven to alter the Stroop effect.

This experiment investigated how visual field position and differing stimuli influenced
the reaction time in naming ink colors. Based on the information above and past studies,
these hypotheses were formulated. The time to name the ink colors will vary with visual
field position. The slowest time should occur when the stimulus appears in the right
visual field because of its association with the left side of the brain. The time to name
congruent stimuli should be faster then the time to name incongruent stimuli. The time to
name ink color will vary with both visual field position and type of stimuli. Time to name
ink colors for congruent stimuli should not vary much with visual field but the time to
name ink color of incongruent should increase as the stimuli gets color to the right
visual field.

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