Millisecond Forums

Random Stimulus Order

https://forums.millisecond.com/Topic16457.aspx

By mrg4 - 6/6/2015

Hey there,

in our recent experiment subejcts have to learn different word-pairs and recall them later.
To avoid primacy/recency effects due to the word-order, we wanted to randomize the order across subjects.

In my solution I used the "noreplacenot" selection-mode. That works almost fine, but the last position always contains the same word.
I have no idea why this happens. Maybe one of you has got a solution to our problem.

Thank you!

Cheers,
Dominik
By Dave - 6/7/2015

You are approaching this the wrong way. Instead of /not constraints you should use a <counter> with selection mode 'noreplace' and selection rate 'always':


<text pos1>
/ items = items
/ position = (50, 10)
/ fontstyle = ("Arial", 2%)
/ select = mycounter
</text>

<text pos2>
/ items = items
/ position = (50, 20)
/ fontstyle = ("Arial", 2%)
/ select = mycounter
</text>

<text pos3>
/ items = items
/ position = (50, 30)
/ fontstyle = ("Arial", 2%)
/ select = mycounter
</text>

<text pos4>
/ items = items
/ position = (50, 40)
/ fontstyle = ("Arial", 2%)
/ select = mycounter
</text>

<text pos5>
/ items = items
/ position = (50, 50)
/ fontstyle = ("Arial", 2%)
/ select = mycounter
</text>

<counter mycounter>
/ select = noreplace(1-5)
/ selectionrate = always
</counter>


<item items>
/1 = "Wort1"
/2 = "Wort2"
/3 = "Wort3"
/4 = "Wort4"
/5 = "Wort5"
</item>

<trial test>
/ stimulusframes = [1=pos1, pos2, pos3, pos4, pos4, pos5]
/ validresponse = (anyresponse)
</trial>