Stroop Effect Essay

The Stroop Effect, does it really exist?

Rachael Hansen

Submitted as a Psychology 201 Practical Report

Due Date: 15th May 2009

Coordinator: Lauren Sailing

ABSTRACT

104 Distance Education University students took part in this study, as part of an assignment to analyse the effect of Interference when completing the Stroop task. Participants were given a series of stimulus to set up the experiment. Each person had a turn of being both the participant and the experimenter. A series of four timed tests were given to individuals who required them to read out aloud the colours that were written on the page. The hypotheses being tested were; interference would be seen when trying to read word
colours when they were written in another colour; pronounceability of words has an impact on interference and slowing down the word recognition response would reduce the amount of interference. Support for all the hypotheses was found through a paired sample T test.

INTRODUCTION

Knowing how the brain functions and the effect this has on different situations is a key factor in Psychologists treating patients (Cohen, McCelland & Dunbar, 1990). In 1955 Psychologist John Ridley Stroop undertook an experiment to explain ‘interference’ and the effect this has on different situations. The Stroop task, and its many variations, is a commonly used tool in cognitive psychology to explore how different types of behaviours interact and the nature of attention and automaticity (Besner, Stolz & Boutlier, 1997).

Cohen et.al. (1990) states, attention focuses on two types of cognitive processes, controlled and automatic. Controlled processes require attention, and are relatively slow, whereas automatic processes are fast and do not require attention for their execution. Besner et.al. (1997), believed reading to be an automatic process as readers cannot refrain from computing the meaning of the word despite explicit instructions not to. They decided to test whether semantic priming during reading can serve to drastically reduce or eliminate Stroop Effect. Their findings indicated that priming may slightly reduce the interference but not drastically or eliminate it. This goes back to the theory of automacity and the brains natural reaction to read the word it sees.

Macleod (1991), states that word reading is very automatic and colour reading is less automatic. More automatic processing can interfere with less automatic processing but not vice versa. This was witnessed in the experiment conducted, whereby participants were required to read incongruent colour names. In the first experiment, there was a significant connection with the Stroop Effect whereby participants showed interference and slower processing time. In the other experiments, some interference occurred but not enough to be a significant difference.

The present study is aimed to test whether the Stroop Effect does indeed exist, by replicating the Stroop Task and using alternate measures to test interference when reading incongruent colour names.
It was hypothesised that the data collected would replicate the Stroop Effect. Participants would experience interference when reading incongruent colour names. It was hypothesised that word pronounceability would have an impact on interference. The participant’s efforts to say the colour name correctly would have an impact on their time to complete the experiment. It was also hypothesised that slowing down the word recognition response would reduce the amount of
interference.

METHOD

Participants

104 Distance Education Students studying Research and Statistics in Psychology at Charles Sturt University. Age, gender and demographics were not specified. Students were bought together to do the experiment during an afternoon lecture.

Apparatus

Green, Blue, Red, Purple Black coloured texta’s, Stopwatch, stimulus materials.

Procedure

Before arriving at residential school, participants were informed they would be undertaking an experiment during their time there. Participants were advised to bring coloured texta’s, a stopwatch and encouraged to access the relevant readings provided to gain insight into the Stroop Paradigm. However, no recording was undertaken as to which students did or did not access this information.

During the afternoon lecture, participants were asked to get into pairs whereby each member would be a participant and an experimenter. Participants were given, 4 experimental conditions. Condition 1-Incongruent Ink colour; Condition 2- the same colour name printed in column two was printed backwards; Condition 3 - required a series of non-words to be written and Condition 4 - a row of capital X’s were written, but the number of X’s had to match the number of letters in the colour name written in column two.

The experimenter was instructed to place the list in front of the participant.
The participant was instructed to name each of the INK colours as quickly as possible, starting at the top of the list. The experimenter signals ‘GO’ and the participant names all of the INK colours. Once the participant has named all of the colours on the list, the participant says STOP. Reaction time is measured with a stopwatch from the time experimenter says GO until the time the participant says STOP. At the completion of each list, reaction time is recorded to the nearest 10th of a second. Experimenter then moves on to the next condition. Once all the conditions are done, the experimenter and participant swap roles. Upon completion of the experiment, everyone handed in the results to collaborate the data. Participants were then asked to
leave.

Results

The first hypothesis predicted that the data collected would replicate the stroop effect, predicting that, interference would occur when reading incongruent colour names. The results of a paired sample T test as summarised in Table 1, provided support for this prediction t (103) = 20.55, p