Number of items shown in the combined parts of the IAT

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Elif Tutku Tunali (Student)

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Jun 22, 2021, 1:49:52 PMJun 22
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Hello, I'm Tutku and currently I am trying to run an IAT on Qualtrics. The code seems to work fine but I have some issues in the combined parts of the task (3,4 and 6,7). The items are not shown in equal numbers. I have tried it multiple times and taking notes of the shown items and I noticed that sometimes it does not show some items either in part 3 or part 4 (same for part 6 and 7) but shows some other items 3 times. I checked this issue with your example IAT and even though in that task, all items were shown, again how many times items were shown were not equal. For example some items were shown both in part 3 and 4, some were shown in only one of them, some were shown 3 times and some were shown only once. Is the task supposed to work like that? and is there any way to make the numbers of shown items equal? Thank you for your time.

Yoav Bar-Anan

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Jun 22, 2021, 4:43:59 PMJun 22
to Elif Tutku Tunali (Student), Minno.js
Hi Tuktu, 

The way it is supposed to work is that from each of the 4 categories, all stimuli will be displayed once before any stimulus would be displayed again. In other words, we choose each stimulus randomly from the category, and we cannot select it again until all the other stimuli in that category are selected. So, it should never happen that, throughout the task, stimulus A of category X would appear n times, and stimulus B of category X would appear n+2 times. n+1 could happen, if the number of trials of each category, throughout the task, is not the product of the number of stimuli for that category and another whole number.
In our example code, we have six stimuli in the two categories and eight stimuli in the two attributes. So, in Block 1 (20 trials -- 10 for each category), within each category, 4 stimuli are supposed to appear twice and 2 stimuli are supposed to appear once. In Block 2 (20 trials -- 10 for each attribute), within each attribute group, 6 stimuli will appear once and 2 stimuli will appear twice. In Block 3 (20 trials) + Block 4 (40 trials), each category will appear, in total, 15 times. In 15 times, all the stimuli must appear at least once. 

If you are certain that this is not the case, please send me the data (csv files), and I'll have a look to see that indeed that is the case, and find the reason for that. 

Thank you,
Yoav

On Tue, Jun 22, 2021 at 8:49 PM Elif Tutku Tunali (Student) <elif....@sabanciuniv.edu> wrote:
Hello, I'm Tutku and currently I am trying to run an IAT on Qualtrics. The code seems to work fine but I have some issues in the combined parts of the task (3,4 and 6,7). The items are not shown in equal numbers. I have tried it multiple times and taking notes of the shown items and I noticed that sometimes it does not show some items either in part 3 or part 4 (same for part 6 and 7) but shows some other items 3 times. I checked this issue with your example IAT and even though in that task, all items were shown, again how many times items were shown were not equal. For example some items were shown both in part 3 and 4, some were shown in only one of them, some were shown 3 times and some were shown only once. Is the task supposed to work like that? and is there any way to make the numbers of shown items equal? Thank you for your time.

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Elif Tutku Tunali (Student)

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Jun 23, 2021, 2:09:25 PMJun 23
to Minno.js
Hello Yoav, 

Thank you for your quick and very detailed turn. We made some changes in the original code because we want to show an item from each category once, either in part 3 or in part 4. We tried to change the numbers of miniblocks and trials a bit more, and now our problem is solved. Thank you for your time again. 

Best,
Tutku.
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