I'm working on programming an experiment in which participant will learn pairs of pictures (i.e. A-B), and later be tested on those pairs. At test, one picture is displayed at the top of the screen (i.e. A) and the participant has to choose between two options (i.e. B and B').
I used noreplace to choose the A item, and then current and noreplacenot to choose the correctly paired item and another item not part of that pair. Sometimes, however, the same image is being displayed for B and B'. I don't know why this is happening - how can I ensure that a different image is selected from the list? Ideally I'd like every B image to serve as the correct answer on one trial and as the incorrect answer on another. See below or full script attached.
<picture Aimage_ABtest_P>
/ items = Aimage_P
/ position = (50%, 25%)
/ select = noreplace
</picture>
<picture Bcorr_ABtest_P>
/ items = Bimage_P
/ hposition = values.hpos_1
/ vposition = 75%
/ select = current(Aimage_ABtest_P)
</picture>
<picture Bincorr_ABtest_P>
/ items = Bimage_P
/ hposition = values.hpos_2
/ vposition = 75%
/ select = noreplacenot(Aimage_ABtest_P)
</picture>
<trial ABtest_P>
/ validresponse = ("1","3")
/ beginresponsetime = 2500
/ ontrialbegin = [values.hpos_1=counter.hposition.selectedvalue; values.hpos_2=counter.hposition.selectedvalue]
/ stimulustimes = [2000 = Aimage_ABtest_P; 2000 = Bcorr_ABtest_P; 2000 = Bincorr_ABtest_P]
/ timeout = 6000
/ iscorrectresponse=[(values.hpos_1 == 25% && trial.ABtest_P.response == 2) || (values.hpos_1 == 75% && trial.ABtest_P.response == 4)]
</trial>