The Stroop Effect Part 3
Can you ignore incongruent information?
Analyze a classic experiment in psychology with this dataset based on the original 1935 paper by John Ridley Stroop. Activities from Stroop’s original datasets are spread across 3 separate activities, it is recommended that you complete them in sequential order to get the most out of them.
Part 1 - How does color interference affect reading time?
Part 2 - How does word interference affect reading time?
Part 3 - How does practice influence interference?
Background
Stroop predicted individual ability to read color names (despite interference of conflicting colors) to be stronger than their ability to correctly identify colors (despite word interference) possibly because the association between words and their meanings is more specific and learned early on compared to the names of colors. However, he wondered if new associations could be formed between previously disparate words and visual stimuli through repeated practice. He predicted that if new associations could be formed through learning, participants would show a decrease in time taken to read the NCWd list with increasing number of days of practice.
In this third dataset, explore if practicing color identification modifies the effect of color interference.
Dataset
In his third experiment, Stroop recorded the time it took for each of the 32 participants (17 men and 15 women) to name colors in the presence of conflicting word stimuli every day, for a period of 8 days using 50 out of the 100 words of the NCWd list.
Variables
Participant ID: A unique ID given to each participant
Sex: Indicates whether the participant was a male (M) or a female (F)
Number of days of practice: Variable indicating the number of days participants had practiced the list (1 - 8 days)
Time to Read: Time it took for a participant to identify colors of words from a list in which each word indicated a different color (NCWd)
Activity
1) State the hypothesis and prediction Stroop was testing in this study with respect to color interference
2) What variables would you need to assess to test the hypothesis and state the type of variable that it is?
3) Make a graph using your selected variables to see how practice affects the ability to correctly identify colors on a Stroop Test. Paste your graph below:
4) What is the equation that best fits the data below? Create a regression line on your graph, and screenshot your new graph below. Paste the equation below your graph.
5) Express in your own words what the equation tells us about the relationship between time to name colors and the duration of practice
6) Do males and females differ in the effect practice can have on their ability to identify colors on a Stroop Test? Select gender as the z-variable. Keep regression lines present, and make sure group by z is selected to give you two different regression lines.
Paste the new graph below, as well as the two new equations.
7) Regression lines are helpful to understand how males and females might vary in their time to read the list over days of practice, but statistics can help add an additional element of understanding.
Remove regression lines, and add descriptive stats by plotting mean-only and 95% CI values.
Remember to treat the X-axis here as a categorical variable to clearly visualize the mean at each point on the X- axis. Paste your graph below
8) To test if the differences between males and females are significant, we need to run graph-driven hypothesis test. Click on the button to see which tests are available to run. Which is best? Why does that test make the most sense?
9) Run the test, and paste the statistical tests of significance below. Include an explanation of what it means.
10) Did individual participants consistently differ in the time it took to name colors? Remove descriptive stats, and set Participant ID as your new z-variable. Add regression lines back in. Paste your new graph below:
11) Look over the slope values of your regression lines. What do they tell you about the role of an individual when it comes to final results?
12) What are some reasons proposed in the literature regarding why the Stroop Effect occurs? Explain any one in detail
13) In his study, Stroop looked at not only the effect of practicing the NCWd list (Naming colors of words when they are written in different colors), but he also tested the effect of practicing this list on participant ability to perform on other tasks such as Naming colors (NC) and reading color names when there is an interference of color (RCNd) etc. Using the simulation model in DataClassroom and reported mean and SD values of participant initial and final scores for the above lists in the paper, can you test what the effect of practice and sex might be on participant initial and final scores? Use appropriate tests of significance for each variable
