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 [:'(]
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.
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
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).
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