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Thread: Randomly present set word pairs

  1. #1
    Join Date
    Nov 2006
    Posts
    1

    Randomly present set word pairs

    Hi there,
    I was wondering if anyone could help me with a problem I'm having setting up my study. Here is what I need to be able to do:
    I have three sets of word pairs: Associated, Unassociated, and Nonword pairs. I have to be able to present the word pairs randomly, but I have to ensure that the prime for that pair and it's target are always presented in the same trial. For instance, I have to ensure that the word "ale" is ALWAYS followed by the word "beer." I cannot for the life of me figure out how to set this up - can anyone give me some pointers? I'm just learning how to use this program but I'm seriously stuck right now. Any help would be greatly appreciated!
    Thanks!!
    Kristen

  2. #2
    Join Date
    Nov 2005
    Posts
    3,328
    Check this out (from the new v2006 user's guide):

    Yoking Random Pairs

    Location:
    …\DirectRT\samples\6 v2006\yoking random pairs

    Sample Description

    This sample demonstrates how to present a stimulus paired with a previous stimulus, when that previous stimulus was randomly chosen. The gets around the fact that you do not know in advance what the previous stimulus was.

    In the past it was difficult to randomly choose a stimulus from a list and then subsequently present a paired or matched stimulus from different list. DirectRT now makes this easy by allowing you to say "pick the item from this list that matches the position of the item I just randomly chose from that list!" Say for example, you want to use a randomly chosen prime/target pairing, where primes and targets are each in their own lists. Choose a random prime as usual by requesting $prime. Then simply ask for &target^-1. Using the & symbol you are requesting a specific item from a list. The -1 value tells DirectRT to use the position equal to the position of the last random stimulus chosen. Use greater negative values to match random picks from farther back.

    On each trial in this sample, a voice file is randomly chosen at the start of each trial. The subsequent stimuli for the trial are all chosen as a function of which voice file was chosen. Try the sample and see--e.g., if the third voice file is chosen, then the subsequent stimuli include the third behavioural description, and third question from each of the question lists.

  3. #3
    Join Date
    Mar 2008
    Posts
    3

    Same random pairs issue, different stimuli

    Hello,

    I am trying to set up a priming experiment which requires prime and target stimuli to be matched in the same trial. Both my primes and targets are word stimuli located in text file lists. For the prime-target stimuli I am using seperate files for the primes and targets. The prime-target pairs are matched by their place in their respective text files.
    I was able to get directRT to randomly sample the prime and choose the correct target from your previous post. However, on all trials, when directRT displays the primes and targets it displays a ".bmp" extension after each prime and target stimuli. For example it will show the prime "cat.bmp" followed by its target "dog.bmp". Can anyone tell me how to correct this?

    Thank you,
    Brandon

  4. #4
    Join Date
    Nov 2005
    Posts
    3,328

  5. #5
    Join Date
    Mar 2008
    Posts
    3

    Fixed it

    Thanks,
    I figured it out. The problem was i didn't add a ~ symbol before each word in my text file lists.

  6. #6
    Join Date
    Nov 2005
    Posts
    3,328
    Ahh.. so you actually wanted text but DirectRT thought you wanted images. Sorry, I missed that when I read your post.

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