Millisecond Forums

Randomizing presentation

https://forums.millisecond.com/Topic12775.aspx

By beccabos - 3/22/2014

Hello! I have a task that includes an image presentation followed by two Likert ratings. The image presentation is set to be part of the first Likert trial and the second Likert trial is separate. This is what I have now:

<likert Image>
/ stimulustimes = [1=fixation; 500=instructlist1; 3000=imagelist1; 8999=erase; 9000=rating; 13500=fixation]
/ pretrialpause = 500
/ responsetime = 9000
/ timeout = 13500
/ anchors = [1="not at all"; 2="not much"; 3="neutral"; 4="some"; 5="a lot"]
/ position= (50, 90)
</likert>

<likert Rating2>
/ stimulustimes = [1=price]
/ pretrialpause = 500
/ responsetime = 1
/ timeout = 4500
/ anchors = [1="$0-$2"; 2="$2-$5"; 3="$5-7"; 4="$7-10"; 5=">$10"]
/ position=(50, 90)
</likert>

<block myblock>
/preinstructions = (instructions)
/trials = [1-20= sequence(Image,Rating2)]
/postinstructions = (thankyou)
</block>


Is the best way to randomize the presentation of the Likert screens to make a different part of the block for the image presentation and then randomize the two Likert screens? E.g.

<trial Image>
/ stimulustimes = [1=fixation; 500=instructlist1; 3000=imagelist1; 8999=erase]
</trial>

<likert Rating1>
/stimulustimes = [1=rating; 4500=fixation]
/ pretrialpause = 500
/ responsetime = 1
/ timeout = 5000
/ anchors = [1="not at all"; 2="not much"; 3="neutral"; 4="some"; 5="a lot"]
/ position= (50, 90)
</likert>

<likert Rating2>
/ stimulustimes = [1=price]
/ pretrialpause = 500
/ responsetime = 1
/ timeout = 4500
/ anchors = [1="$0-$2"; 2="$2-$5"; 3="$5-7"; 4="$7-10"; 5=">$10"]
/ position=(50, 90)
</likert>

<block myblock>
/preinstructions = (instructions)
/trials = [1-20= Image, noreplace(Rating1, Rating2)]
/postinstructions = (thankyou)
</block>



Thank you so much for the help...
By Dave - 3/22/2014

You can do that, but the syntax in your <block> element's /trials attribute is botched (read: invalid). The correct way to do this is:

/ trials = [1,4,7,10,13,16,19=image; 2,3=noreplace(Rating1, Rating2); 5,6=noreplace(Rating1, Rating2); ...]