Selection and randomization of stimuli

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Selection and randomization of stimuli

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SilvioM	SilvioM posted 3 Years Ago Topic Details Share Topic
Group: Forum Members Posts: 8, Visits: 105	Dear all, I have been working on an Inquisit script (please find it attached) and I am struggling with the stimuli selection. I have a block with four different types of trials: approaching stim_1 in the upper part of the screen with distractor_1; approaching stim_1 in the lower part of the screen with distractor_1; approaching stim_1 in the upper part of the screen with distractor_2; approaching stim_1 in the lower part of the screen with distractor_2. There are eight stimuli by category (ie eight stimuli for stim_1 ; eight stimuli for distractor_1 ; eight stimuli for distractor_2) and overall, I would like to display 128 trials (32 per type of trials). I also would like that, at the block level, each possible pair of stimuli (64 pairs = stim_1 with distractor_1 and 64 pairs = stim_1 with distractor_2) would be displayed only once, with stim_1 being randomly displayed either in the upper part of the screen or either in the lower part of the screen. I have mainly used this post to compute the actual code : https://www.millisecond.com/forums/Topic2273.aspx Any help would be greatly appreciated! Thank you very much, warm regards, S.M Attachments forum.zip (149 views, 5.00 KB)
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Dave	Dave posted 3 Years Ago ANSWER Post Details Share Post
Group: Administrators Posts: 12K, Visits: 98K	+x SilvioM - 9/23/2021 Dear all, I have been working on an Inquisit script (please find it attached) and I am struggling with the stimuli selection. I have a block with four different types of trials: approaching stim_1 in the upper part of the screen with distractor_1; approaching stim_1 in the lower part of the screen with distractor_1; approaching stim_1 in the upper part of the screen with distractor_2; approaching stim_1 in the lower part of the screen with distractor_2. There are eight stimuli by category (ie eight stimuli for stim_1 ; eight stimuli for distractor_1 ; eight stimuli for distractor_2) and overall, I would like to display 128 trials (32 per type of trials). I also would like that, at the block level, each possible pair of stimuli (64 pairs = stim_1 with distractor_1 and 64 pairs = stim_1 with distractor_2) would be displayed only once, with stim_1 being randomly displayed either in the upper part of the screen or either in the lower part of the screen. I have mainly used this post to compute the actual code : https://www.millisecond.com/forums/Topic2273.aspx Any help would be greatly appreciated! Thank you very much, warm regards, S.M What are your concrete questions
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Dave	Dave posted 3 Years Ago ANSWER Post Details Share Post
Group: Administrators Posts: 12K, Visits: 98K	+x Dave - 9/23/2021 +x SilvioM - 9/23/2021 Dear all, I have been working on an Inquisit script (please find it attached) and I am struggling with the stimuli selection. I have a block with four different types of trials: approaching stim_1 in the upper part of the screen with distractor_1; approaching stim_1 in the lower part of the screen with distractor_1; approaching stim_1 in the upper part of the screen with distractor_2; approaching stim_1 in the lower part of the screen with distractor_2. There are eight stimuli by category (ie eight stimuli for stim_1 ; eight stimuli for distractor_1 ; eight stimuli for distractor_2) and overall, I would like to display 128 trials (32 per type of trials). I also would like that, at the block level, each possible pair of stimuli (64 pairs = stim_1 with distractor_1 and 64 pairs = stim_1 with distractor_2) would be displayed only once, with stim_1 being randomly displayed either in the upper part of the screen or either in the lower part of the screen. I have mainly used this post to compute the actual code : https://www.millisecond.com/forums/Topic2273.aspx Any help would be greatly appreciated! Thank you very much, warm regards, S.M What are your concrete questions > I also would like that, at the block level, each possible pair of stimuli (64 pairs = stim_1 with distractor_1 and 64 pairs = stim_1 with distractor_2) would be displayed only once, with stim_1 being randomly displayed either in the upper part of the screen or either in the lower part of the screen. Then the two trials Approach_PA_SED_top and Approach_PA_SED_bottom should sample from the same set of two counters, not two separate sets of counters. Same for the two trials Approach_PA_NEU_top and Approach_PA_NEU_bottom.
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SilvioM	SilvioM posted 3 Years Ago ANSWER Post Details Share Post
Group: Forum Members Posts: 8, Visits: 105	My question is: how can I make each pair of stimuli (stim_1 with distractor_1 and stim_1 with distractor_2) appear only once? At the moment, as I pick 32 trials from the first trial condition (ie stim_1 on the top of the screen) and 32 trials from the second trial condition (ie stim_1 on the bottom of the screen), some pairs of trials may be redondant across conditions, and some pairs of trials may not be displayed. I hope that it is clearer now, thank you very much for your support.
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Dave	Dave posted 3 Years Ago ANSWER Post Details Share Post
Group: Administrators Posts: 12K, Visits: 98K	+x SilvioM - 9/23/2021 My question is: how can I make each pair of stimuli (stim_1 with distractor_1 and stim_1 with distractor_2) appear only once? At the moment, as I pick 32 trials from the first trial condition (ie stim_1 on the top of the screen) and 32 trials from the second trial condition (ie stim_1 on the bottom of the screen), some pairs of trials may be redondant across conditions, and some pairs of trials may not be displayed. I hope that it is clearer now, thank you very much for your support. As I said in my previous response, you ought to have the two NEU trials sample from the same two counters, and same thing for the two SED trials. 64 SED target-distractor combinations <counter counter_Approach_PA_SED_target> / select = noreplace / items = ( 1,1,1,1,1,1,1,1, 2,2,2,2,2,2,2,2, 3,3,3,3,3,3,3,3, 4,4,4,4,4,4,4,4, 5,5,5,5,5,5,5,5, 6,6,6,6,6,6,6,6, 7,7,7,7,7,7,7,7, 8,8,8,8,8,8,8,8) </counter> ## I create all combinations for target stimuli <counter counter_Avoid_SED_distractor> / select = current(counter_Approach_PA_SED_target) / items = ( 1,2,3,4,5,6,7,8, 1,2,3,4,5,6,7,8, 1,2,3,4,5,6,7,8, 1,2,3,4,5,6,7,8, 1,2,3,4,5,6,7,8, 1,2,3,4,5,6,7,8, 1,2,3,4,5,6,7,8, 1,2,3,4,5,6,7,8) </counter> and distracting stimuli with <trial Approach_PA_SED_top> / ontrialbegin = [values.Approach_PA_SED_top = counter.counter_Approach_PA_SED_target.selectedvalue; values.Avoid_SED_bottom = counter.counter_Avoid_SED_distractor.selectedvalue; ] / stimulusframes = [1=focuspoint; 100 = Approach_PA_SED_top, Avoid_SED_bottom, moi] / validresponse = ("t", "b","g") / correctresponse = ("t") / timeout = 10000 / branch = [if (trial.Approach_PA_SED_top.response == 0) trial.tooslowfb] / branch = [if (trial.Approach_PA_SED_top.error) trial.errorfb] / branch = [if (trial.Approach_PA_SED_top.correct) trial.correctfb_Approach_PA_SED_top] </trial> <trial Approach_PA_SED_top> / ontrialbegin = [values.Approach_PA_SED_top = counter.counter_Approach_PA_SED_target.selectedvalue; values.Avoid_SED_bottom = counter.counter_Avoid_SED_distractor.selectedvalue; ] / stimulusframes = [1=focuspoint; 100 = Approach_PA_SED_top, Avoid_SED_bottom, moi] / validresponse = ("t", "b","g") / correctresponse = ("t") / timeout = 10000 / branch = [if (trial.Approach_PA_SED_top.response == 0) trial.tooslowfb] / branch = [if (trial.Approach_PA_SED_top.error) trial.errorfb] / branch = [if (trial.Approach_PA_SED_top.correct) trial.correctfb_Approach_PA_SED_top] </trial>
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