| Background:
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| Stroop (1935) presented subjects with words which were printed in different colored inks. In some lists (congruent) the words spelled out color names which were the same as the ink colors (e.g. the word "red" written in red ink). In other lists (incongruent), the words were color words which DID NOT agree with the ink colors (e.g. the word "red" written in blue ink). When the subjects were given the two kinds of list and asked to name the ink colors as quickly as possible, they were much slower and made many more mistakes when words and inks disagreed (incongruent) compared to when the words and inks agreed (congruent). This is called the Stroop effect. One explanation for the Stroop effect is that for most of us, reading is a very well-practiced and automatic process, and in the presence of words, occurs whether we want it to or not. The reading interferes with the response of naming the ink color when the two are different.
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| Stimulus conditions:
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| 1.) Congruent. The congruent list will contain 24 words which spell out the names of colors. Each word will be printed in the same color ink as the color name. Subjects are asked to name the ink colors and are relatively fast and accurate on this list. Although they automatically read the color names in this list, because the color name agrees with the ink color, there is little interference.
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| 2.) Incongruent. The incongruent list will contain 24 words which spell out the names of colors. Each word will be printed in an ink which is different from the color name. Subjects are slower and make more mistakes when naming the ink colors in this list because they automatically read the color name which is different from the correct response (ink color). This condition produces a lot of interference.
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| Consent:
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| Before you begin, tell your potential subject that you are conducting a psychology experiment in visual perception. Ask them if they would like to participate. (This is a pretty informal and watered-down way of getting informed consent, but it will be okay for our projects.) Donít give your potential subjects much more information about the theory you are testing, because this will affect you results. You can fill in the details during the debriefing.
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| Method:
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| Each of your 10 subjects will participate in both the congruent and incongruent conditions. Half will get the congruent list first, followed by the incongruent list, while the other half will get the reverse order. You should randomly assign each subject to an order*. Only use subjects who are 12 yrs. old or older, and are native speakers of English (or are very fluent in English). Once you've randomly assigned a particular subject to an order, read the instructions to the subject. Ask if the subject understands the instructions before you begin. Get your timer ready. Remind your subject to say, "Done!" when they finish the list. When you are both ready to begin, give the subject the first list, say "Go!", and measure the total time it takes for the subject to finish reading all the words. When they say, "Done!", stop your timer. The difference between the starting time and the ending time is the total time that it took your subject to read the list.
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| After you've finished a list, write down the time you measured on the line at the bottom of the data sheet. Now do repeat the same procedure for your second list.
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| Subject instructions:
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| I am going to show you a list of words written in different colored inks. Please say the ink color of each word out loud as quickly as possible. As soon as you have finished responding to one word, move onto the next one, until you are finished with the whole list, as quickly as possible. When you get done, please say, "Done!". Remember to say the ink colors out loud -- ignore what the words actually spell out. (Repeat the instructions if necessary before you give the next list.)
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| Congruent and incongruent stimulus lists: (see attached pages)
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| These lists were constructed to possess the following characteristics: 4 color words which were one syllable in length; with each possible color word used 6 times; each ink color corresponding to the words was also used 6 times.
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| Debriefing:
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| Again, we will not do a formal debriefing for the projects. When the experiment is over, you must ask if the subject would like to explain what the study is about -- if the answer is "Yes", then explain. Also, offer to address any questions or comments about the experiment.
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| Data summary:
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| The data sheet should have the list reading times for both the congruent and the incongruent lists for each subject. Also, you should write down which order you used for presenting the lists. (Remember, you will have 2 orders, and 5 subjects in each order.) You will turn in this sheet in with your final project and will eventually will be part of your notebook.
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| Questions: Add the answers to these questions to the end of your final project report.
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| 1.) What does is mean to say that a perceptual skill like reading is "automatic"? What are the advantages and disadvantages to automaticity? (If you need a hint, try looking back at pp. 304-306.)
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| 2.) You were asked to randomly assign your subjects to the list orders (congruent first vs. incongruent first). Why did I ask you to do this?
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| 3.) Why is it probably a good idea to limit your subjects to people who are fluent English speakers/readers? What do you think would happen the ink-naming if the letters in your lists did not spell color words, but were nonsense strings of letters, like ìSFDTYî?
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