Hi,

I'm working on an alcohol-specific version of the Go/No-Go Task.

I have 40 different pictures either framed yellow or blue. Depending on the color of the frame the participants have to either react or not.
Now I have to problems:
1) I tried to create two groups in order to counterbalance the colors. Group 1 (go=yellow; no-go=blue) seems to work just fine. As soon as I want to run the experiment with group two (go=blue; no-go) the experiment won't run because it is "Unable to initialize <picture stimuli> item number 0. Verify the item exists and is correctly defined." My stimulus value right now is 0.

2) I have 320 trials in total and want to present every picture exactly 6 times as a go-trial and 2 times as a no-go-trial. The order of the presented pictures should be random.

Thank you for your help!

<expt GoNoGoTask1>
/ subjects = (1 of 2)
/ groupassignment = groupnumber
/ onblockbegin = [values.expcondition = 1]
/ onexptbegin = [values.format1 = "gelb"; values.format2 = "blau"]
/ preinstructions = (intro)
/ postinstructions = (end)
/ blocks = [1=practiceblock; 2=testblock]
/onexptend = [values.completed = 1]
</expt>

<expt GoNoGoTask2>
/ subjects = (2 of 2)
/ groupassignment = groupnumber
/ onblockbegin = [values.expcondition = 2]
/ onexptbegin = [values.format1 = "blau"; values.format2 = "gelb"]
/ preinstructions = (intro)
/ postinstructions = (end)
/ blocks = [1=practiceblock; 2=testblock]
/onexptend = [values.completed = 1]
</expt>

<block testblock>
/ trials = [1-320=noreplace(notarget, notarget, notarget, notarget, notarget, notarget, target,target)]
/ preinstructions = (Experiment)
/ onblockbegin = [values.targettype = 0; values.correctresp = 0; values.trialcount = 0; values.correctcount = 0; values.count_go = 0; values.correct_go = 0; values.count_nogo = 0; values.correct_nogo = 0; values.commissionerror = 0; values.sumrt = 0; values.omissionerrors = 0]
</block>

<picture stimuli >
/ items = stimuli
/ select = values.stimulus
/ position = (50%,50%)
/ size = (30%,30%)
/erase = false
</picture>

<trial target>
/ ontrialbegin = [if(values.expcondition == 1) values.stimulus=list.t1_stimuli.nextvalue;values.trialcount += 1; values.count_nogo += 1; values.targettype = 2 ||
if(values.expcondition == 2) values.stimulus=list.t2_stimuli.nextvalue;values.trialcount += 1; values.count_nogo += 1; values.targettype = 2]
/ stimulustimes = [0=blankscreen; 1=stimuli; 250=blankscreen; 1150=blankscreen]
/ validresponse = (57, noresponse)
/ correctresponse = (noresponse)
/ beginresponsetime = 1
/ posttrialpause = 500
/ response = timeout(1000)
/ ontrialend = [if (trial.target.correct) values.correctcount += 1 else values.commissionerror += 1]
/ ontrialend = [if (trial.target.correct) values.correct_nogo += 1]
/ recorddata = true
</trial>

<trial notarget>
/ ontrialbegin = [if(values.expcondition == 1) values.stimulus=list.nt1_stimuli.nextvalue;values.trialcount += 1; values.count_nogo += 1; values.targettype = 2 ||
if(values.expcondition == 2) values.stimulus=list.nt2_stimuli.nextvalue;values.trialcount += 1; values.count_nogo += 1; values.targettype = 2]
/ stimulustimes = [0=blankscreen; 1=stimuli; 250=blankscreen; 1150=blankscreen]
/ validresponse = (57, noresponse)
/ correctresponse = (57)
/ beginresponsetime = 1
/ posttrialpause = 500
/ response = timeout(1000)
/ ontrialend = [if (trial.notarget.correct) values.correctcount += 1]
/ ontrialend = [if (trial.notarget.correct) {values.correct_go += 1; values.sumrt += trial.notarget.latency}]
/ ontrialend = [if (trial.notarget.error) values.omissionerrors += 1]
/ recorddata = true
</trial>