How do I influence the selection of an item (group1) based on previous items (group2)?

element0 — Wed, 12 Nov 2014 04:11:51 GMT

Hello,
I am new to Inquisit and I am stuck at this point: I sample my stimuli randomly from two item groups (50%/50%). Each stimulus from the treatment group corresponds to one stimulus from the control group with the same number (e.g. "t1.wav" – "k1.wav"). Currently after a stimulus from one group is selected, the corresponding one in the other group might get selected too. How do I prevent that?

(e.g. I don’t want item "t6.wav" to be selected after "k6.wav" has already been presented to the participant and vice versa)

Thank you very much for your help!
Christian

<item treatment>
/ 1 = "audio\t1.wav"
/ 2 = "audio\t2.wav"
/ 3 = "audio\t3.wav"
/ 4 = "audio\t4.wav"
/ 5 = "audio\t5.wav"
/ 6 = "audio\t6.wav"
/ 7 = "audio\t7.wav"
/ 8 = "audio\t8.wav"
/ 9 = "audio\t9.wav"
/ 10 = "audio\t10.wav"
/ 11 = "audio\t11.wav"
/ 12 = "audio\t12.wav"
/ 13 = "audio\t13.wav"
/ 14 = "audio\t14.wav"
/ 15 = "audio\t15.wav"
/ 16 = "audio\t16.wav"
</item>

<item control>
/ 1 = "audio\k1.wav"
/ 2 = "audio\k2.wav"
/ 3 = "audio\k3.wav"
/ 4 = "audio\k4.wav"
/ 5 = "audio\k5.wav"
/ 6 = "audio\k6.wav"
/ 7 = "audio\k7.wav"
/ 8 = "audio\k8.wav"
/ 9 = "audio\k9.wav"
/ 10 = "audio\k10.wav"
/ 11 = "audio\k11.wav"
/ 12 = "audio\k12.wav"
/ 13 = "audio\k13.wav"
/ 14 = "audio\k14.wav"
/ 15 = "audio\k15.wav"
/ 16 = "audio\k16.wav"
</item>

<sound treatment_sound>
/items = treatment
/playthrough = true
/select = noreplace
/resetinterval = 0
</sound>

<sound control_sound>
/items = control
/playthrough = true
/select = noreplace
/resetinterval = 0
</sound>

<trial soundplay_trial>
/stimulusframes = [1= noreplace(treatment_sound, control_sound)]
/timeout = 10
/validresponse = (noresponse)
/pretrialpause=1000
</trial>

<block trialblocks>
/trials = [1-8 = soundplay_trial]
</block>

<expt>
/ blocks = [1=trialblocks;2=trialblocks]
</expt>

RE: How do I influence the selection of an item (group1) based on previous items (group2)?

element0 — Wed, 12 Nov 2014 04:11:51 GMT

Thank you very much, Dave! That solved it!

Christian

RE: How do I influence the selection of an item (group1) based on previous items (group2)?

Dave — Tue, 11 Nov 2014 10:05:51 GMT

You need to set up a single selection pool for the two <sound> elements via a <list> and then sample from that pool without replacement.

<list mylist>
/ poolsize = 16
</list>

<sound treatment_sound>
/items = treatment
/playthrough = true
/select = list.mylist.nextindex
/resetinterval = 0
</sound>

<sound control_sound>
/items = control
/playthrough = true
/select = list.mylist.nextindex
/resetinterval = 0
</sound>

Millisecond Forums » Millisecond Forums » Inquisit 4 » How do I influence the selection of an item (group1) based on previous items (group2)?

How do I influence the selection of an item (group1) based on previous items (group2)?

RE: How do I influence the selection of an item (group1) based on previous items (group2)?

RE: How do I influence the selection of an item (group1) based on previous items (group2)?