Stop Signal task,about data collection and interpretation


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Iris520
Iris520
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I know...When inhibition is successful, SSD increases by 50   msec; when inhibition is unsuccessful, SSD decreases by 50   msec.


but whatever the inhibition is successful or not,the SSD is still stay the minSSD 50msec.I don't know why [:'(]


Dave
Dave
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 so, I needs to change "probability to respond when a stop-signal is present [expressions.p_rs]"?


No! You cannot and should not change it. This is an empirical datum. It means the person who produced the data set responded on 100% of stop-signal trials. If a person *never* suppresses a response despite the presence of a stop-signal, there is *no* basis to change the stop-signal-delay.


Your question(s) suggest that you have not yet fully grasped the reasoning behind stop-signal paradigms. I thus urge you to re-read the literature carefully.


Iris520
Iris520
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 so, I needs to change "probability to respond when a stop-signal is present [expressions.p_rs]"?


/ p_rs = (1-(values.ss_ncorr/values.ss_ntotal))*100


But how?


many many thanks...Dave



Dave
Dave
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The minimum SSD is 50 ms. Since your data show responses on *every* stop-signal trial (p_rs=100), there is no basis to adjust the SSD upwards.


For details, please refer to the literature, specifically Verbruggen et al. (2008).


Iris520
Iris520
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Hello,everyone.I am a student.I have some problems in data collection and interpretation at Stop Signal task.I don't know why" values.ssd/expressions.p-rs/expressions.ssd、ssrt、sr-rt "show like the following.Is that normal? ssd ranges from 50 to 1150,but,there is always 50...


I am weak at English,hoping you can understand my description.many thanks for your reply.


                                                                                                                                                              Iris





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