By Marina - 9/4/2014
Hi,
I am putting together an experiment that is a variation of the digit span memory task.
Participants are presented with a 4-digit number, and have to enter the digits in a text box, but replace all 1s with 9s and 5s with 8s. (so if they see 2343, they would enter 2343, but if they see 2345 they would enter 2348)
I want to evaluate whether participants got the correct answer on each trial, but am running into some problems.
Here is some of the syntax I use (I could send you the full syntax if you want)
<expressions>
/fullnumber = evaluate (text.digit1.currentitem*1000 + text.digit2.currentitem*100 + text.digit3.currentitem*10 +text.digit4.currentitem)
/d1 = values.d1
/d2 = values.d2
/d3 = values.d3
/d4 = values.d4
/fullcorrect = (values.d1*1000) + (values.d2*100) +(values.d3*10) +values.d4
/correctanswer = values.correctanswer
</expressions>
<openended practice_add3>
/ stimulustimes = [0 = signal; 1000 = eraser; 1100 = digit1 , digit2, digit3, digit4; 3100 = eraser, response]
/ mask = positiveinteger
/ inputdevice = keyboard
/ charlimit = 4
/ size = (15%, 2.5%)
/ validresponse = (anyresponse)
/timeout = 7000
/ontrialend = [if (text.digit1.currentitem !=5 && text.digit1.currentitem !=1) values.d1 = text.digit1.currentitem; if (text.digit1.currentitem ==5) values.d1 = 8; if (text.digit1.currentitem ==1) values.d1 = 9]
/ontrialend = [if (text.digit2.currentitem !=5 && text.digit2.currentitem !=1) values.d2 = text.digit2.currentitem; if (text.digit2.currentitem ==5) values.d2 = 8; if (text.digit2.currentitem ==1) values.d2 = 9]
/ontrialend = [if (text.digit3.currentitem !=5 && text.digit3.currentitem !=1) values.d3 = text.digit3.currentitem; if (text.digit3.currentitem ==5) values.d3 = 8; if (text.digit3.currentitem ==1) values.d3 = 9]
/ontrialend = [if (text.digit4.currentitem !=5 && text.digit4.currentitem !=1) values.d4 = text.digit4.currentitem; if (text.digit4.currentitem ==5) values.d4 = 8; if (text.digit4.currentitem ==1) values.d4 = 9]
/iscorrectresponse = [evaluate (openended.practice_add3.response - expressions.fullcorrect)==0]
/ontrialend = [values.correctanswer = expressions.fullcorrect]
/ontrialend = [if (openended.practice_add3.correct == true) values.numcorrectadd3practice = values.numcorrectadd3practice + 1]
/ buttonlabel = "Press CTRL+ENTER to continue"
/ errormessage = true(error,400)
/correctmessage = true(yescorrect, 400)
</openended>
digit1 through digit4 are randomly generated digits. I know the program is correctly recording the presented numbers, what should be the 'correct' response, and the response I input (because I ask for the relevant expressions to be saved in the output file), but it is not recognizing correct responses as being correct, so I think my problem is with the /iscorrectresponse line.
I also tried the following:
/iscorrectresponse = [openended.practice_add3.response == expressions.fullcorrect]
and that does not work either.
Any other suggestions would be appreciated!
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By Dave - 9/4/2014
It's quite simple. /ontrialend attributes are executed *at the very end of the trial*, i.e., *after* any response evaluation (e.g. via /iscorrectresponse) has occurred.
Since you do all the things that *would* be necessary to determine response correctness /ontrialend, it is bound to fail. The information isn't available at the point in time correctness evaluation happens.
Instead you'll want to do something along the lines of
<values>
/ digitstring = ""
/ correctstring = ""
</values>
<block myblock>
/ trials = [1-4=practice_add3]
</block>
<openended practice_add3>
/ ontrialbegin = [values.digitstring=""; values.correctstring="";]
/ ontrialbegin = [values.digitstring = concat(concat(concat(text.digit1.nextvalue,text.digit2.nextvalue),text.digit3.nextvalue),text.digit4.nextvalue);
values.correctstring = replaceall(values.digitstring,"5","8");
values.correctstring = replaceall(values.correctstring,"1","9");
]
/ stimulustimes = [0 = digit1 , digit2, digit3, digit4, debug]
/ mask = positiveinteger
/ inputdevice = keyboard
/ charlimit = 4
/ size = (15%, 2.5%)
/ validresponse = (anyresponse)
/ iscorrectresponse = [openended.practice_add3.response==values.correctstring]
/ buttonlabel = "Press CTRL+ENTER to continue"
</openended>
<text digit1>
/ items = ("1","2","3","4","5","6","7","8","9")
/ position = (40%,40%)
</text>
<text digit2>
/ items = ("1","2","3","4","5","6","7","8","9")
/ position = (45%,40%)
</text>
<text digit3>
/ items = ("1","2","3","4","5","6","7","8","9")
/ position = (55%,40%)
</text>
<text digit4>
/ items = ("1","2","3","4","5","6","7","8","9")
/ position = (60%,40%)
</text>
<text debug>
/ items = ("Digit String = <%values.digitstring%> | Correct String = <%values.correctstring%>")
/ position = (50%, 5%)
</text>
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