Millisecond Forums

Responses not recognised in StopSignal Task

https://forums.millisecond.com/Topic19061.aspx

By Lizzy - 5/11/2016

Hi,

I downloaded the StopSignal task from the test library (http://www.millisecond.com/download/library/StopSignalTask/), however when I run it, the program fails to recognise my responses. The output file shows a 0 in the 'response' column on every trial, even though I was tapping the D and K keys. In a version where I built in an extra task prior to the stop-signal task, responses to that other task are recognised appropriately. When I run the monkey through the stopsignal task, responses are recognised and the output file shows 32s and 37s in the 'response' column, as it should. This failure to recognise responses happens when I run the program on my PC as well as when I run it through Inquisit web, on my iPhone. Any idea what could be causing this issue?

Incidentally, yesterday the data also failed to save when I ran the stopsignal on my desktop, however data was saved when running the task online through the app (on an iphone). I downloaded the latest version of Inquisit 5 and that seems to have fixed the saving problem. My system information shows that the program is registered. 

Thanks
By Dave - 5/11/2016

There is a mistake in the <parameters> element in the posted script. The trialduration parameter is mistakenly set *way* too short, i.e., the trial will basically stop listening for responses before you ever get the chance to submit one.

<parameters>
/ resetpracticessd = false
/ leftkey = 32
/ rightkey = 37
/ minssd = 10
/ maxssd = 300
/ adjustment = 10
/ ssd_start = 50
/ pretrialpause = 0
/ posttrialpause = 0
/ trialduration = 500
/ waitbetweenblocks = 0
/ p = 0.5
</parameters>

 In addition, the /pretrialpause parameter is also not at the default value it should be set to. If you change those two to

<parameters>
/ resetpracticessd = false
/ leftkey = 32
/ rightkey = 37
/ minssd = 10
/ maxssd = 300
/ adjustment = 10
/ ssd_start = 50
/ pretrialpause = 500
/ posttrialpause = 0
/ trialduration = 2000
/ waitbetweenblocks = 0
/ p = 0.5
</parameters>

the script should work as intended.

Hope this helps.
By Lizzy - 5/15/2016

Thanks Dave, that solved the issue!