Millisecond Forums

Data Element Stimulus Onset Time for a repeated stimulus

https://forums.millisecond.com/Topic14640.aspx

By Marcel - 10/16/2014

Hi,

The following script contains a stimulus presented twice within a trial. The stimulus onset time recorded in the data file does not appear to update the time from the initial presentation? 

*.iqdat attached.


<defaults>
/screencolor = (128, 128, 128)
/txbgcolor = (128, 128, 128)
/txcolor = white
/fontstyle = ("Arial", 10%)
</defaults>

<block one>
/trials = [1=MyTrial;2=MyTrial2; 3=MyTrial3]
</block>

<trial MyTrial>
/stimulusframes = [1=Frame1; 7=blank; 8=Word1; 14=blank; 15=Word2]
/validresponse = (57)
</trial>

<trial MyTrial2>
/stimulusframes = [1=Frame1; 7=blank; 8=Word1; 14=blank2; 15=Word2]
/validresponse = (57)
</trial>

<trial MyTrial3>
/stimulusframes = [1=Frame1; 7=blank; 9=Frame1]
/validresponse = (57)
</trial>

<text Frame1>
/items = ("Frame1")
</text>

<text Word1>
/items = ("Word1")
</text>

<text Word2>
/items = ("Word2")
</text>

<shape blank>
/shape = rectangle
/size = (700, 150)
/position = (50, 50)
/color = (128, 128, 128)
</shape>

<shape blank2>
/shape = rectangle
/size = (700, 150)
/position = (50, 50)
/color = (128, 128, 128)
</shape>




By Dave - 10/16/2014

Yes, that is a known limitation in current releases. If a stimulus is presented repeatedly in a given trial, the reported onset currently is that of the 1st presentation. There are ways to work around that:

http://www.millisecond.com/forums/FindPost10700.aspx