Duration in sampler item and response time

sflu

Hi,

I have a sampler item that plays a sound followed by a keyboard response item. From my understanding, if i set duration of the sampler to 0 responses are collected from sound onset.

Now, I don't want to collect responses in the first 200 ms the sound is playing, so I set duration to 200, right? And if I then want response times to be calculated from sound onset (while preventing responses in the first 200 ms) do I simply add 200 ms to the response_time variable?

Thanks!

eduard

Hi,

Yeah, sounds legit.

Eduard

sflu

Hi @eduard,

Thanks for your response! In addition to response_time, I recorded the timestamps for time_sampler and time_keyboard_response, so if I subtract the keyboard timestamp from the sampler one, it right now comes out at about ~216. So it would be "more accurate" to add that to the response_time instead of the 200ms I initially specified in the sampler duration (if I want sound onset RTs)? Or does this not matter? Apologies in advance if this doesn't really make sense.

Thank you!

eduard

Hi,

It depends on whether you care for absolute response times. If you do, you need as accurate an estimate as possible 216 ms. If you don't, it doenst matter what you use. After all you are essentially just adding a constant to your actual RTs. Then you can use 216 or 200, or nothing at all for that matter.

By the way, maybe a bit late, but maybe Co-routines are something you should look at. Sounds like you implement your own, sort of:

https://osdoc.cogsci.nl/4.0/manual/structure/coroutines/#using-coroutines

Also, maybe useful, if you wonder why 216ms:

https://osdoc.cogsci.nl/4.0/manual/timing/#making-the-refresh-deadline

Hope this helps,

Eduard

sflu

Hi @eduard,

Thanks for your response! There was some variability (so not always 216 ms), so I ended up calculating the difference between the two timestamps and adding that to the RT. I did look into co-routines initially but since I had to run the experiment online it wasn't an option. Maybe it is now, I'll have to check out the latest version.

Thanks for the links, I'll check them out!