The Expectations of the Stroop Effect

The Stroop effect is an experimental design that analyzes our automatic responses when observing incongruent stimuli. In this study, a short experimental naming test will be performed with both neutral and interference conditions. A picture of fruit was displayed on a screen with either an incongruent or neutral word underneath. Members of an Indiana University lab ranging in age from 19-to 25 participated in the study. The experiment follows a within-participants layout. 

Each participant encounters each condition in a randomized order. The neutral condition presented faster results from participants on average. This result confirms the expectations of the Stroop effect (Stroop, 1935). Such results show that when an interfering variable is presented, our automatic processing often lengthens our response times because of the distraction. This has implications for many different fields of study and our understanding of human thought processing.

Computers, consoles, smartphones are all examples of sophisticated pieces of technology that many of us encounter every day. However, they are still capable of mistakes and glitches. Much like a computer, our brains are capable of mistakes and glitches as well. One might identify the Stroop affect as a glitch in the way we analyze stimuli. The Stroop paradigm investigates response time when one is exposed to an incongruent stimulus. The Stroop experiment initially timed respondents as they read words that were a different color than what the word said. Respondents on average took longer to read words that contained an interference (Stroop, 1935). This experiment paved the way for many future experiments in the field of psychology.

The Stroop effect has serious implications on the world of psychology. Its significance lies in how it helps us understand the functionality and processes of the human brain. Understanding the Stroop affect can lead to breakthroughs in the field of psychological sciences and the medical field. A common rationale for the Stroop affect is the identification of reading in the experiment as an automatic process. Reading is so engrained in most individuals' brains that they do it subconsciously. When an interference, or in-congruency, is exposed to an individual this is when the ‘glitch’ occurs.

There are a variety of scenarios in which the Stroop test can be applied. One such example is a study performed in 2009 that analyzed response time, memory, and emotional arousal with the Stroop test as part of their testing. The study found that emotional arousal, when exposed to a stimuli, can affect both memory and response time (Dresler, Mériau, K, Heekeren, & van der Meer, 2009). The Stroop effect is more than a simple test of interference, it is a template that allows us to make deeper connections in the field of psychology. 

The Stroop effect was also used in another study which analyzed response time in aphasic patients who had difficulty communicating. This study was performed to help researchers better understand the minds of aphasic patients (Hashimoto, Thompson, 2010). The ultimate question to this research is how an automatic process affects response time when exposed to an incongruency.

In order to better understand how an automatic process affects response time, I will be performing an experiment in which participants are presented with a fruit that has either a neutral or contradicting word underneath the photo. This will be the independent variable. The dependent variable will be the response times of the participants as they read off the name of the fruit. The test will analyze how the automatic process of reading interferes with a simple naming task.

Prior Stroop research would suggest that participants will take longer to respond to the naming task when encountering the interference condition. This is because reading is an automatic process, and therefore when the word is incongruent but related to the subject matter participants will take longer to respond. They will also be more likely to respond with the wrong name. Since reading is an automatic task, and identifying an object is not, readers will automatically begin reading the word (Monohan, 2001). This version of the Stroop effect should yield similar results to past research.

The purpose of this study was to determine whether photos were easier to identify when paired with either an incongruent word or a neutral word. This experiment is based on the Stroop test, or the Stroop effect, which shows an interference stimulus paired with a task stimulus causes an individual to take longer to respond. In Stroop's original experiment he used words with incongruent colors to see if participants took longer to identify the color of the word (Stroop, 1935). The Independent variable in this study is whether the participant is viewing fruit with an incongruent word underneath or the name of an animal. The dependent variable is how quickly respondents finish each task. If the task correlates with past experiments, it will take respondents longer to identify an image if the name of a different fruit is listed under the picture of a fruit.

Participants for this experiment were recruited through a Methods of Experimentation Lab at Indiana University. Between the ages of 19 and 25 ten female students participated in the study. Every participant was subjected to both the interference and neutral condition. The participants in the study were not offered any incentive for their participation.

Participants were asked to read off the name of fruit from the program PowerPoint from Microsoft. Words in size 24 black Calibri font were centered under Google image photos of random, well-known fruit. Each condition contained 20 different slides, and in each condition pictures of fruit were not re-used. Slides were organized in a random order. These tasks were performed on a Windows PC using the space key on a standard keyboard to navigate the slides. The PowerPoint slides were displayed on dell 15” computer monitor. 

To keep results consistent, the same photos were presented in each condition, but the order was changed so participants would not memorize the slides. Images were stretched to roughly the same size and only one fruit was included in each image to prevent confusion. Participants were not told the hypothesis and which condition was timed first was random as a counterbalancing measure. Response time was recorded using a Samsung Galaxy S10+ Stopwatch app. Results and demographic information were then recorded through Excel from Microsoft.

The experiment was carried out in an Indiana University lab setting. Students volunteered one at a time to partake in the experiment at random. The task at hand was explained to the participants as follows: “You will be presented with a set of slides. Please name the fruit in the picture on each slide. If you are not familiar with the name of the fruit, just say skip. Whenever you are ready to begin, please hit the space bar.” If the participant did not know the name of the fruit, they were asked to simply say skip rather than spend extra time remembering the name of the fruit. 

Once the participant understood the instructions, they were asked to press space to begin the experiment. To avoid any bias in the experiment, five students began with the interference condition and proceeded to the neutral condition. The other five students started with the neutral condition. Once they began, I would simply hit start on the timer and then hit end once they finished each condition.

Independent variables in this study were manipulated by either placing a neutral word or incongruent word underneath the photo of a fruit. The dependent variable was measured by timing the participants. Two instances were recorded where participants did not know the name of the fruit. This could have potentially altered the results because participants were then able to name the fruit faster in a subsequent task. Results remained similar in all conditions despite participants forgetting the name of certain fruit.

The average time for all participants during the interference condition was 20.57 seconds. The average time for all participants in the neutral condition was 19.26. The P value for this experiment was .2147 after running a pairing simulation 10,000 times and the mean difference was 1.3. This is the likelihood that we would achieve results at least this extreme. Based on the result, we cannot reject the null hypothesis.

Results from the experiment show us that on average, participants took longer to respond to the interference task. The observed mean individual difference for this experiment was 1.3. Meaning, on average it took participants at 1.3 seconds longer overall to respond to the interference task. This is significant because it falls in line with the proposed hypothesis: that participants would take longer to respond if an incongruent stimuli was present. In this case, if a word that was not neutral to the image was underneath the image, it attracted the attention of the participants and lead to automatic processing. The incongruent stimuli served to distract the participant by averting their focus to the wrong stimulus.

There were some limitations to the experiment. One such limitation was how well each fruit was known. Some of the fruit presented in the slides were not known to participants, and in turn resulted in longer response time. To improve this, more common fruit should be displayed, or participants should be exposed to the pictures beforehand. Another limitation of the study was the language of the study. One participant was not familiar with some of the English words for certain fruit, which led to some confusion. 

The solution to this is the same as the previous limitation. Finally, not every participant sat in the same place while reading the slides. It is possible that some participants were able to sit more comfortably which in turn may have made reading the slides an easier task. To resolve this, all participants in the future should sit in the exact same environment in the same seating arrangement.

We can make this assumption based on prior research on the Stroop effect. The original Stroop experiment found similar results as well. In the original Stroop experiment, participants took longer to read a word that was a different color than what the word stated (Stroop, 1935). Another automatic process that has been tested in relation to the Stroop experiment showed that the automatic task of emotion paired with an interference condition produced longer response times (Dresler, 2009). 

With this research in mind, it is difficult for our brains to avoid performing automatic tasks, and therefore it makes sense that it would take longer to respond to a test when something that arouses our automatic processing is present. Future research could help us better understand new ways to override automatic processing. More research could also help implicate the use of the Stroop effect in other fields of science.

In a broader sense, the application of the Stroop effect across different situations can help us draw connections in how the brains works. Another example of how the findings from the Stroop affect can influence other fields of science was performed when a group of researchers tested aphasic patients to determine how the Stroop interference affected those who had difficulty communicating (Hashemite 2010). All these studies concluded respondents took longer when faced with an interfering stimulus, further reinforcing the results of this experiment. However, to better understand the Stroop effect in relation to mental health, further research must be conducted.

There is great significance in the repeated success of the Stroop experiment when researching automatic processes. It helps researchers and professionals devise new approaches when trying to describe the way we think. Something as simple as a distraction can shed light on other portions of brain science and bring us closer to the progress. This study displays the effects of an interference, or distraction, when performing a simple naming task.