Providing feedback on stimuli from stimlist (case 22054)
Providing feedback on stimuli from stimlist (case 22054)
Hi there,
I want to use stimlist so that stimuli will be presented randomly without replacement ($), but - I also want to provide feedback (<). Each stimulus on the list has 4 possible responses of which only 1 is correct. I want to provide "wrong" feedback for the other 3 responses. Is there any way to indicate for each stimulus in the list which response will lead to the "wrong" feedback (e.g., add a < near each stimulus in the list, as is done with regular stimuli in the time column)?
Thanks!
Tali
Can you give me an example of what you mean by "each stimulus on the list has 4 possible responses of which only 1 is correct?"
Can you give me an example of what you mean by "each stimulus on the list has 4 possible responses of which only 1 is correct?"
Say I'm running a 4 color Stroop task, so I have 4 possible responses (e.g., green, red, blue, yellow), but for the stimulus red written in green, the only correct answer is green. I want participants to get a "wrong" feedback if they respond red, blue or yellow to this stimulus. (of course each color is assigned a key, e.g., D for red, F for green, G for blue, and H for yellow).
Thanks!
Take a look at the attached .csv input file. Taking your example of the stroop task, I modified one of the stroop examples from the Samples folder that comes with DirectRT.
If you want to give feedback of correct or incorrect, this requires defining which keypresses are correct or incorrect. However, this can't be done when using a sitmlist without random replacement. So, to achieve the effect, you have to explicitly put the each stimuli in the .csv input file. You can then use the same positive nonzero integer in the wgr field of all the trials to get random presentation of the trials without repetition of already presented trials.
Let me know if this is what you wanted.
Thanks, but this is not what I meant - the attached csv file is what I already know how to do...
My problem is that on some blocks I want to present only some of the stimuli (e.g., i have a total of 20 stimuli, but want to present only 8), and in a random (with no replacement) order. That's why I have to use a stimlist, and that's why I need to connect correct/incorrect responses to the stimuli in the stimlist.
To present a subset of trials that are randomized with the wgr field, insert a row into the block of these trials after the last row of the number of them you want presented. If you have 8 trials but only want 4 presented, simply put a trial after the fourth row of all the rows that have the same nonzero positive integer in the wgr field. Take a look at the attached file for an example.
Note how the trial 6 uses a value of 0 in its wgr field to ensure that only four trials with with the value of 1 in the wgr field will be presented. DirectRT will still select from all of the trials with a value of 1 in the wgr field, but only present four of them in this example.
Trial 6 also skips over the rest of the trials by using the skip command to jump to trial 11. You can use this feature to jump to anywhere you want in your .csv input file.
This looks like exactly what I meant! Thanks! Will try this and let you know if indeed so. Thanks!
You're welcome. Let me know how it goes.
Hi Jason,
Just got around to that, and what you suggested works great. But my problems are not yet solved...
The jump function you suggested works only if a response is given. So if I put a line with rt:any>20 after 4 trials (out of 8 trials) it does jump to trial 20. That's great.
However, what I need and does not seem to work, is having it jump without a response, say after 100ms. So putting 100>20 in the time column does not work...
Any suggestions?
Thanks!
Please tell me the full version number (i.e., 20xx.x.xxx) of your copy of DirectRT. You can find it by opening DirectRT and selecting Help>About DirectRT from the main menu bar.
It's 2012.4.0.164
Thanks.
Please send me a copy of the latest version of your DirectRT file and anything else I need to run it in DirectRT. You can either upload it here or send it to me directly at support@empirisoft.com (please reference case 22054)
