Millisecond Forums

> For example, in the 'Practice trials' section, I have one of three different stimuli randomly appearing after a key-press (spacebar) - either a
> green, red, or blue circle, staying on screen for 400ms, and then the participant is asked to judge the time interval between keypress and
> the image appearing (between 0-900ms). Currently I have these three stimuli in separate trials, but I was wondering if there was a simpler > method of having them all in the same 'trial', as it were. No data needs to be recorded during these trials, so I don't require any stimuli
> values to be recorded.

You can alter a <shape>'s color at runtime by setting the shape.shapename.color property. I.e, your practice phase can be reduced to:

<block PracticeBlock>
/trials = [1-30 = practice]
</block>

<trial practice>
/stimulustimes = [500 = cross]
/correctresponse = (" ")
/pretrialpause = 500
/branch = [trial.practicedot]
/recorddata = false
</trial>

<trial practicedot>
/stimulustimes = [1 = whiterectangle]
/ ontrialbegin = [shape.circle.color = list.colors.nextvalue]
/ontrialbegin = [trial.practicedot.insertstimulustime(shape.circle, list.targetdurationP.nextvalue)]
/ontrialbegin = [trial.practicedot.insertstimulustime(shape.whiterectangle, list.targetdurationP.currentvalue+400)]
/ontrialend = [trial.practicedot.setstimulustime(shape.whiterectangle, list.targetdurationP.currentvalue)]
/ontrialend = [trial.practicedot.resetstimulusframes(100)]
/timeout = (list.targetdurationP.currentvalue+1000)
/recorddata = false
</trial>

<shape circle>
/shape = circle
/size = (1% * 3/4 * 10, 10%)
/position = (50%, 50%)
/erase = false
</shape>

<list colors>
/ items = (red, green, blue)
/ poolsize = 30
</list>

<list targetdurationP>
/items = (0, 100, 200, 300, 400, 500, 600, 700, 800, 900)
/replace = false
</list>

<shape whiterectangle>
/shape = rectangle
/size = (70%, 70%)
/color = white
/position = (50%, 50%)
/erase = false
</shape>

<text cross>
/items = ("+")
/color = (0,0,0)
</text>

> [... ] There are 20 scenarios, with good and bad versions (thus, 40 in total), and I was wondering if there was a method to not having an
> awfully long script. Each participant should only experience one scenario (either the good or bad version) once, such that there should
> be 20 'trials' (i.e. different scenarios) in total per participant.

You'd simply need to make sure that the two versions are sampled from the same pool of 20 item number: Once e.g. item number 5 has been selected in the "good" condition, it cannot be selected anymore for the "bad" condition. Simple example:

<block myblock>
/ trials = [1-20 = noreplace(goodscenario, badscenario)]
</block>

<trial goodscenario>
/ stimulusframes = [1=good]
/ validresponse = (57)
</trial>

<trial badscenario>
/ stimulusframes = [1=bad]
/ validresponse = (57)
</trial>

<text good>
/ items = gooditems
/ txcolor = green
/ select = list.scenariolist.nextindex
</text>

<text bad>
/ items = baditems
/ txcolor = red
/ select = list.scenariolist.nextindex
</text>

<item gooditems>
/ 1 = "s1 - good"
/ 2 = "s2 - good"
/ 3 = "s3 - good"
/ 4 = "s4 - good"
/ 5 = "s5 - good"
/ 6 = "s6 - good"
/ 7 = "s7 - good"
/ 8 = "s8 - good"
/ 9 = "s9 - good"
/ 10 = "s10 - good"
/ 11 = "s11 - good"
/ 12 = "s12 - good"
/ 13 = "s13 - good"
/ 14 = "s14 - good"
/ 15 = "s15 - good"
/ 16 = "s16 - good"
/ 17 = "s17 - good"
/ 18 = "s18 - good"
/ 19 = "s19 - good"
/ 20 = "s20 - good"
</item>

<item baditems>
/ 1 = "s1 - bad"
/ 2 = "s2 - bad"
/ 3 = "s3 - bad"
/ 4 = "s4 - bad"
/ 5 = "s5 - bad"
/ 6 = "s6 - bad"
/ 7 = "s7 - bad"
/ 8 = "s8 - bad"
/ 9 = "s9 - bad"
/ 10 = "s10 - bad"
/ 11 = "s11 - bad"
/ 12 = "s12 - bad"
/ 13 = "s13 - bad"
/ 14 = "s14 - bad"
/ 15 = "s15 - bad"
/ 16 = "s16 - bad"
/ 17 = "s17 - bad"
/ 18 = "s18 - bad"
/ 19 = "s19 - bad"
/ 20 = "s20 - bad"
</item>

<list scenariolist>
/ poolsize = 20
</list>

> I am aiming to recruit 80 participants ideally, so, additionally, each possible scenario (both the good and bad versions) should be seen
> an equal number of times, with both outcomes having been produced equally across all participants (40 possible scenarios x 2
> outcomes).

This is not possible -- when a participant takes the experiment, Inquisit has no way of knowing how often a given scenario has already occurred in either the good or bad version with other / previous participants. Hence, there can be no guarantee whatsoever that, say, scenario #4 is administered equally often in the bad as well as good version across participants (and so forth for all the other scenarios).

To ensure such a distribution, you'd have to abandon randomization and define different "sets" of scenarios satisfying that requirement (equal distribution of all scenarios in good vs. bad version across all participants). You would have to implement / administer those sets as between-subjects conditions.

> A final query is the recording of which scenario took place - I currently have values.scenario set as /ontrialend = [values.scenario =
>  good/bad], but I was wondering if it were possible to have this information recorded in the stimuli trial (e.g., trial.trialS01G), so that both
> the scenario and the stimulus-outcome are recorded on the same data line.

I don't understand this question.

#1: The syntax in the script you attached is broken:

<trial S01G_Scenario_Good>
/stimulustimes = [1 = good_1]
/correctresponse = (57)
ontrialend = [values.scenario = good]
/branch = [trial.trialS01G]
</trial>
...
<trial S01B_Scenario_Good>
/stimulustimes = [1 = bad_1]
/correctresponse = (57)
ontrialend = [values.scenario = bad]
/branch = [trial.trialS01G]
</trial>

ought to read

<trial S01G_Scenario_Good>
/stimulustimes = [1 = good_1]
/correctresponse = (57)
/ ontrialend = [values.scenario = "good"]
/branch = [trial.trialS01G]
</trial>
...
<trial S01B_Scenario_Good>
/stimulustimes = [1 = bad_1]
/correctresponse = (57)
/ ontrialend = [values.scenario = "bad"]
/branch = [trial.trialS01G]
</trial>

#2: When you set values.scenario to, say,  "bad" in <trial S01B_Scenario_Good>, it will still say exactly that in the data file's "next line", the one for <trial trialS01G>. In other words, you have the scenario and stimulus information on the same data line.

Hi Dave,

Many thanks for your assistance. I followed your advice and created a successful script.

I have another a follow-up experiment script that is similar, but I'm also at a loss. Essentially, I have the same 20 scenarios with a good/bad variation for each scenario (thus 40 in total). In this experiment, the participant has two buttons to press - one that produces a good outcome and the other that produces the bad, after they have read the scenario (participants will be trained previously to associate each of the two buttons with either the good/bad outcome), where the idea is is that the participant will choose the outcome they think should deservingly be the result of the scenario.

For example, here is scenario 1:

*********
Scenario 1
*********

<trial S01G_Scenario>
/stimulustimes = [1 = good_1]
/validresponse = (16, 25)
/responsetrial = (16 = trialS01G)
/responsetrial = (25 = trialS01B)
/ontrialend = [values.scenario = "good"]
/recorddata = true
</trial>

<trial S01B_Scenario>
/stimulustimes = [1 = bad_1]
/validresponse = (16, 25)
/responsetrial = (16 = trialS01G)
/responsetrial = (25 = trialS01B)
/ontrialend = [values.scenario = "bad"]
/recorddata = true
</trial>


<trial trialS01G>
/stimulustimes = [1 = whiterectangle]
/ontrialbegin = [trial.trialS01G.insertstimulustime(picture.S01G, list.targetdurationE.nextvalue)]
/ontrialbegin = [trial.trialS01G.insertstimulustime(text.s01g_r, list.targetdurationE.currentvalue+1000)]
/ontrialbegin = [trial.trialS01G.insertstimulustime(shape.whiterectangle, list.targetdurationE.currentvalue+5000)]
/ontrialend = [trial.trialS01G.setstimulustime(shape.whiterectangle, list.targetdurationE.currentvalue)]
/ontrialend = [values.onset = list.targetdurationE.currentvalue]
/ontrialend = [trial.trialS01G.resetstimulusframes(100)]
/ontrialend = [values.stimuli = S01G]
/timeout = (list.targetdurationE.currentvalue+5000)
/branch = [surveypage.te]
/recorddata = true
</trial>

<trial trialS01B>
/stimulustimes = [1 = whiterectangle]
/ontrialbegin = [trial.trialS01B.insertstimulustime(picture.S01B, list.targetdurationE.nextvalue)]
/ontrialbegin = [trial.trialS01B.insertstimulustime(text.s01b_r, list.targetdurationE.currentvalue+1000)]
/ontrialbegin = [trial.trialS01B.insertstimulustime(shape.whiterectangle, list.targetdurationE.currentvalue+5000)]
/ontrialend = [trial.trialS01B.setstimulustime(shape.whiterectangle, list.targetdurationE.currentvalue)]
/ontrialend = [values.onset = list.targetdurationE.currentvalue]
/ontrialend = [trial.trialS01B.resetstimulusframes(100)]
/ontrialend = [values.stimuli = S01B]
/timeout = (list.targetdurationE.currentvalue+5000)
/branch = [surveypage.te]
/recorddata = true
</trial>

However, I need two conditions. One in which that the participant's response has a 50-50 chance to produce either outcome (i.e., random, despite their button press-association training), and one in which the participant's response has a 75-25 chance to produce the outcome they intended with their response. I haven't found a way to manipulate this using the responsetrial element, so I imagine it is something to do with lists (which I'm terrible at). Thus far I have:

<list Scenario_1_50>
/items = (S01G, S01B)
/itemprobabilities = (0.5, 0.5)
/replace = true
</list>

<list Scenario_1_75_Good>
/items = (S01G, S01B)
/itemprobabilities = (0.75, 0.25)
/replace = true
</list>

<list Scenario_1_75_Bad>
/items = (S01G, S01B)
/itemprobabilities = (0.25, 0.75)
/replace = true
</list>

- but I'm unable to incorporate them into the trial sequence properly, especially as I need to ensure that both the scenario, the participant's response, the probability to which they can produce their desire outcome, and the outcome itself, all need to be recorded properly.

I hope there's a way to resolve this, and I apologise if there's an easy solution that I haven't realised. Please let me know if you need any more information, or if you'd like me to attach the whole script.

Many thanks,
Josh

You cannot use the /responsetrial attribute. You need to use /branch and set up your lists properly.

<trial sometrial>
...
/ branch = [if (trial.sometrial.response == 16) list.example.nextvalue]
...
</trial>

<list example>
/ items = (trial.good, trial.bad)
...
</list>

<trial good>
...
</trial>

<trial bad>
...
</trial>

That's brilliant, thanks Dave.

Josh