Good morning, Your input has been a huge help with understanding these results. I appreciate your time on this matter. If I have any further questions, I'll be sure to reach back out! Thank you again.
Best, Amrita Arcot ________________________________ From: smuel...@obereed.net <smuel...@obereed.net> Sent: Tuesday, October 15, 2019 4:04 PM To: Arcot, Amrita <avr5...@psu.edu> Cc: pebl-list@lists.sourceforge.net <pebl-list@lists.sourceforge.net> Subject: Re: [Pebl-list] Simple Reaction Time Test and Response Amrita, During any trial, there is a period before the stimulus appears during which a response could be made, which you might call the 'waiting period' or inter-trial interval (ITI). The delay variable in the data file indicates the programmed time between when the trial actually started and _either_ a stimulus was presented, or a response was made. The variable delay2 indicates the actual measured delay, which is usually a few ms longer than programmed, because timing is going to be synched to the refresh cycle. Notice that on the first line you examined, the delay2 is shorter than delay, which means they made an (incorrect) anticipatory response--before the stimulus was presented. An x is put into resp1 when this is done. The task is designed so that the subject does not know their early responses are being recorded, but this is how you can tell. It will only record the first early response--if they jam the x key multiple times, you won't know it. Note that the trial cannot proceed until they make an actual response after the stimulus appears, so there will always be a response in column resp2. In theory, you could modify the task to have a timeout, but I never incorporated that logic. The 550 on the first line still indicates the time from the onset of the x until the response key was pressed, so it is a valid response time. But because they made an anticipatory response on that trial, you may want to discard it during analysis. If you look at the final report (see example below), the information about resp1 is not used. That is, the 'anticipations' just code those trials whose response is < 150 ms, whether or not they made a response during the waiting period. Hope this help, Shane ------------------------------------------------------ Report for PEBL Simple Response Time Task Version 0.2 PEBL Version 2.1 Started at: Tue Oct 15 15:58:02 2019 Finished at: Tue Oct 15 15:59:29 2019 http://pebl.sf.net Participant Code: 20 Stimulus:X ------------------------------------------------------ Statistic Value ------------------------------------------------------ Number of blocks 2 Trials per blocks 25 Stimulus X Total Trials 25 Anticipations (<150) 2 Delayed Responses (>3000) 0 Correct RT Mean 343.521 Correct RT Median 301 Correct RT Min 252 Correct RT Max 847 Correct RT SD 121.811 Delay N Mean Std. Dev -------------------------------------- 250 4 490.5 164.065 500 4 582.5 212.302 750 5 321.6 22.9922 1000 5 344 48.6292 1250 5 321.6 32.5613 1500 5 279.4 13.8795 1750 5 291.8 24.4246 2000 5 308.2 23.0686 2250 5 291.8 13.9771 2500 5 281 28.8375 ------------------------------------------------------ On 2019-10-10 18:23, Arcot, Amrita wrote: Hello, My name is Amrita and I'm a PhD student at Penn State University. My lab has joined a study currently utilizing PEBL for its cognitive assessment of women of reproductive age. I have been tasked with understanding why a single response SRT would have two responses recorded in a trial. A few papers have suggested computer or keyboard associated latency periods (maybe this results in double depression of the key?). I am quite new to PEBL, and was hoping for guidance on this matter. I have attached a screenshot of four data points to this correspondence. I truly appreciate your help as we continue with this project. Thank you for your time! [cid:15711698575da62641c8860136033656@obereed.net] Best Regards, Amrita Arcot Amrita Arcot, RDN, LDN Ph.D. Student | Department of Nutritional Sciences The Pennsylvania State University 218 Chandlee Laboratory, University Park, PA 16802 [cid:15711698575da62641c8e6a893921672@obereed.net] http://nutrition.psu.edu<http://nutrition.psu.edu/> _______________________________________________ Pebl-list mailing list Pebl-list@lists.sourceforge.net<mailto:Pebl-list@lists.sourceforge.net> https://lists.sourceforge.net/lists/listinfo/pebl-list<https://nam01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.sourceforge.net%2Flists%2Flistinfo%2Fpebl-list&data=02%7C01%7Cavr5374%40psu.edu%7C166dc2fb7957451c5f6208d751aadd51%7C7cf48d453ddb4389a9c1c115526eb52e%7C0%7C1%7C637067666615283055&sdata=jq4HSujAuLicHJ5OyCP7%2BIyoJVoC7HTzakaIh5KoW24%3D&reserved=0>
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