Stroop Effect

An investigation of the human brain and its ability to get confused easily.

Maria Guedilla

Problem

There needs to be a way to show how easily the brain gets confused.

Research

      A common experimental psychology test is called the Stroop Effect. The Stroop Effect measures the time it takes for a person to name the color of printed words. John Ridley Stroop was the man that found out about this in 1935 and wrote an article over it.

    The human brain has trouble processing two pieces of information at the same time; language and color, which is what the Stroop Effect tests. It also measures a person’s speed reaction. The Stroop Effect is not completely understood, but something that is known is that it can measure capacity to direct attention. It is simply an experiment to show how easy it is to mess with slash confuse the human brain. When people do this experiment for the first time, they tend to get frustrated with themselves and start to laugh out of their frustration, so it is something to take note of when testing people. This experiment should prove that it is difficult compared to regular color matching words. The Stroop Effect is sort of the same as patting your head with one hand and rubbing your stomach with the other hand. There are many and different ways to do this experiment. A dependent variable for this experiment could be time; how long it takes to read the whole list CORRECTLY. Another dependent variable is to see which people of the tested start to laugh out of frustration. There are many independent variables for this experiment which include: adding in other words, turning the words at a ninety degree, practice, adding random strings of letters, age of the people being tested, and doing the experiment in a well- lit room compared to a darker room. All of these could have effects on the result, and therefore be possible independent variables. Another way to do the experiment is to test a group of people in another language (Spanish for example) and compare it to a group of people that did the same experiment in English.

     Adding in words other than colors could affect a person’s time to read the whole list of printed words correctly, by throwing them off. There would be no forewarning, so this could just confuse them and affect their time.

    Turning the words at a ninety degree angle could make the reading aloud portion harder for the person being tested. It might look weird to the person’s brain and make them go slower.

     If random strings of letters are added, then a person’s brain could try to make out words from it, when really there are no words. The person could try to read into it and have it completely throw them off.

    Apparently little kids tend to do better in this experiment than older people. It is possible because their minds are still developing and they get things mixed up all the time. If I tested a group of kids and a group of adults, I would compare the average time of each group and try to understand as to why that is.

      The darkness of the room a person is being tested in could also be a factor that affects the time it takes for the list of colors to be read correctly. Some people study in a darker room and it helps them do better on a test, so how dark a room is, could be a do-able independent variable.

      I could test a group of people in English, then I could take another group of people and have them do the same exact test, in the same conditions but in another language. For example, if the group of people speak Spanish, then the list they get will be in Spanish. This would compare the average time of the groups and see if languages could have an effect on time.

     Practice would be crucial if I decide to use it as an independent variable. A person would be allowed two times to do the experiment, but their time would not really count until the third time.

     The Stroop Effect is not hard to test; it just has many ways to do the experiment and has many independent variables to choose from. Even though the Stroop Effect has multiple ways to be tested and has a lot of independent variables, any way the Stroop Effect is tested; the dependent variable would really just be time.

Hypothesis

If I test twenty five people reading the colors of printed words twice (Stroop Effect), then most of the test subjects will take less time on the second trial because they have already seen the list once before and will try to get a faster time the second trial.

Materials

*1 Computer

*1 Colored Printer

*1 Timer/ Stopwatch

*1 Laminator (OPTIONAL)

*25 People

Procedures

  1. On a computer, type up a list of 30 different colors. (Color words CAN repeat)
  2. Change the color of the word, to a color that is not the word. (EX: The color word red, not in red. RED)
  3. Do step number 2 on all 30 words typed.
  4. Print out the list of colors in the non-matching colors.
  5. OPTIONAL: Laminate the paper.
  6. Have a designated timer (Same person will be the timer for every person tested).
  7. Have the test subject start to read the COLOR of the word, not the word itself, after the timer person says to start.
  8. Once the test subject is done, record the time it took them to finish reading the list CORRECTLY in the data table.
  9. Note how many times the person messes up in the data table. (The person that does this will do it for every test subject.)
  10. Repeat steps 7-10, for a second trial.
  11. Repeat steps 7-10 for all twenty five people being tested.
  12. Record the average of the twenty five people’s first trial time in the data table.
  13. Record the average of the twenty five people’s second trial time in the data table.
  14. Record the average of the twenty five people’s number of errors in the data table (1st and 2nd trial in their place in the data table).

Variables

  1. Independent Variable- Number of Trials
  2. Dependent Variable- Time (Seconds)
  3. Control- No one doesn’t receive the variable
  4. Experimental Group- All twenty-five test subjects
  5. Factors Held Constant- Same person controlling the timer and same person noting the number of errors

Purpose

If a person does two trials of seeing a list of words in non-matching colors and reading the color of the word aloud, will the second trial have a faster time and have fewer errors made?

The purpose of this lab is to know if after doing the experiment once if the second trial will go smoother.

Data

Analysis

     The amount of time it takes to read a whole list of non-matching color words correctly takes less time in a second trial than in a first trial done as well as less errors are made the second trial. For the first trial, the average time was 33.0056 seconds and the average errors made for the first trial was 1.52 errors, meanwhile, for the second trial, the average time was 30.1188 seconds and the average errors made for the second trial was 0.96 -less than one error-. Right off the bat it can be seen that the second trial had better averages than the first, but to make sure that the difference is significant a t-test had to be made to confirm that. The difference between the trials is 0.003012282 which is less than 0.05 and therefore means that the difference is high and that the second trial’s average time was faster than the first trial. Another thing to notice is the difference between the trials for the number of errors made which is 0.023518369, again it is less than 0.05 so the difference is significant, making the second trial number of errors made smaller than first trial’s. Therefore, all of this data shows that it takes less time in a second trial to read a whole list of non-matching colors correctly and that less errors are made in a second trial.

    The reason as to why these results were seen is because the human brain has trouble processing two pieces of information at the same time: language and color. More likely than not, the test subjects had not done anything like the experiment before and this was something new for them and therefore harder in the first trial. But afterwards in the second trial since the test subject had done it once before, the brain of the person knew what to look for and knew how to complete the task more efficiently. After doing it one time, it was easier for the person to get a faster time and make fewer errors.

Calculations & Statistical Analysis


Formula for Mean for BOTH Trials’ Times and Errors:

Test Subject #1 Time or Error for Trial 1 or Trial 2 + Test Subject #2 Time or Error for Trial 1 or Trial 2 + Test Subject #3 Time or Error for Trial 1 or Trial 2 + Test Subject #4 Time or Error for Trial 1 or Trial 2 + Test Subject #5 Time or Error for Trial 1 or Trial 2 + Test Subject #6 Time or Error for Trial 1 or Trial 2 + Test Subject #7 Time or Error for Trial 1 or Trial 2 + Test Subject #8 Time or Error for Trial 1 or Trial 2 + Test Subject #9 Time or Error for Trial 1 or Trial 2 + Test Subject #10 Time or Error for Trial 1 or Trial 2 + Test Subject #11 Time or Error for Trial 1 or Trial 2 + Test Subject #12 Time or Error for Trial 1 or Trial 2 + Test Subject #13 Time or Error for Trial 1 or Trial 2 + Test Subject #14 Time or Error for Trial 1 or Trial 2 +Test Subject #15 Time or Error for Trial 1 or Trial 2 + Test Subject #16 Time or Error for Trial 1 or Trial 2 + Test Subject #17 Time or Error for Trial 1 or Trial 2 + Test Subject #18 Time or Error for Trial 1 or Trial 2 + Test Subject #19 Time or Error for Trial 1 or Trial 2 + Test Subject #20 Time or Error for Trial 1 or Trial 2 + Test Subject #21 Time or Error for Trial 1 or Trial 2 + Test Subject #22 Time or Error for Trial 1 or Trial 2 + Test Subject #23 Time or Error for Trial 1 or Trial 2 + Test Subject #24 Time or Error for Trial 1 or Trial 2 + Test Subject #25 Time or Error for Trial 1 or Trial 2 Equals a BIG NUMBER.

BIG NUMBER DIVIDED BY 25

Time Average First Trial:

40.33 + 28.85 + 23.7 + 37.33 + 34.55 + 22.38 + 36.26 + 31.13 + 49.74 + 29.88 + 37.1 + 27.72 + 24.37 + 32.8 + 36.27 + 30.95 + 34.85 + 28.81 + 27.58 + 37.5 + 31.23 + 32.91 + 38.2 + 28.12+ 42.58 = 825.14

825.14/25 = 33.0056

Error Average First Trial:

3 + 2 + 1 + 4 +1 + 3 + 2 + 4 + 1 + 1 + 1 +1 +2 + 2 + 1 + 3 + 2 +3 + 1 = 38

38/ 25 = 1.52

Time Average Second Trial:

31.91 + 29.39 + 25.57 + 34.68 + 32.95 + 20.89 + 31.3 + 34.05 + 38.4 + 24.63 + 36.48 + 23.14 + 24.85 + 34.55 + 37.6 + 29.48 + 29.57 + 22.9 + 32.22 + 32.52 + 27 + 33.22 + 24.34 + 23.55 + 37.78 = 752.97

752.97/ 25 = 30.1188

Error Average Second Trial:

2 + 2 + 1 + 2 + 1 + 2 + 1 + 1 + 1 + 2 + 2 + 1+ 1 + 1 + 1 + 1 + 1 + 1 = 24

24/25 = 0.96

   These statistical results mean that the difference between each trial for the Time is significant for the probability (Which is what it is) is below 0.05. This is also true for the difference between each trial for the Errors. It is now clearly seen that Trial 2 had a better average time as well as a better errors made average.

Conclusion

   The amount of time it takes to read a whole list of non-matching color words correctly takes less time in a second trial than in a first trial done, as well as less errors are made the second trial. My hypothesis was supported because twenty five people read the colors of printed words twice and most of the test subjects took less time on the second trial because they had already seen it once before and tried to get a faster time on the second trial. The faster average time is what proves that most of the test subjects took less time on the second trial. The purpose of this lab was achieved and this is known for the second trial went smoother (After doing it once) as seen in the data.

Sources of Error

     It is very possible for me to have not clicked the stopwatch button AS SOON as the person began the experiment and it is possible that a couple of seconds may have been added to the recorded time, just because it is hard to stop the stopwatch exactly the moment when the last syllable is said. Another aspect that could’ve given me unreliable results is the possibility that one of the test subjects already did the Stroop Effect experiment with someone else. Even though it isn’t the same colors, the test subject knows the concept and can be good at it without me even knowing.

Improvement

     This experiment’s design could be improved by instead of testing twenty five and having each person do it twice, to have less people and more trials. For example, five people could be the test subjects and each person does the experiment five times. This would give for a better data to be analyzed and easier to see how the number of trials affects the results. However, to continue on with this project, I could do this lab with the same people a year from now. I would compare their first trial and second trial times as well as the number of errors made in the first and second trial. I would take note of whether or not there was some improvement or if it was even worse than the original.

Application

     My experiment can show if someone is partially colorblind because some of the colors looked similar even though they weren't the same color. It can help identify if a person has a hard time seeing a certain color as it should be. This experiment can also be used to show how easy it is to mess with the brain, with even something as simple as this experiment for it doesn't seem very hard but once it is done it gets complicated. It is important to know that the brain gets confused without difficulty so as students we should exercise our brain more and be people with keen minds.

All pictures taken by yours truly.