Hello, I am debugging my log files to ensure that reaction times came in alright, and I have the following three questions that I ask in order to understand the log file information… (1) In a log file, are the times of the “DATA Keydown” the exact time that the keyboard sends the information, or i…

Hey again! It’s the time that the event handler of the key gets called. See this line . I know KeyboardEvents themselves also have a timestamp, but as far as I know, that one isn’t more accurate. See my “Mental Chronometry in the Pocket” paper and its online appendix. It’s the keydown (so when the …

I do want to follow up about point (3) Investigating the time stamps in the log file, it seems that the EXP logs are all 16 milliseconds (one frame duration) away from eachother. I took this as evidence that it is the time after the actual flip, but I was not sure how to further verify that. How ca…

Hey again, As far as I know, you can’t establish this, since there is no way to synchronize timestamps logged in JS with what’s happening on the screen. In my “Mental Chronometry in the Pocket” paper, I tried some stastitical approaches to figure it out, by assuming timestamps logged before flip N …

I’m looking for a rough approximation of when the stimulus of the routine first appears. This serves to verify the reaction times are coming in as intended, and also I’m trying to use this as an easy way to get a rough approximation of the RSI. When I assume that the EXP timestamps are roughly when…

Digging through the scheduler code, which I can not understand well as I’m a beginner in Javascript. It appears that requestAnimationFrame comes after .render() in the .start() function of the Scheduler. Could this have something to do with the behavior I’m getting? See below for source code: /**…

Having some trouble saying something sensible about your second-last post, but I can about your last post. If I’d rewrite this in an example, that might clear things up. It goes a bit like this: // Define update function update = () => { // Draw stuff requestAnimationFrame(update); } requestAni…

Thanks, I will make a more clear detailed example. Now, my goal is to use the log file to obtain the reaction time of a participant on a trial, assuming that we want the reaction time from approximately the onset of the stimuli in the trial, and I marked the “Sync to Screen Timing” to ensure that i…

You’re going deep :). OK, presently, I’m not that deep into these parts of PsychoJS itself, because until now I’ve mainly worked on automated end-to-end testing. I do know there are some plans to work a bit on timestamps, so what I’ll do is this: put your post in a internal list, keep my eyes out fo…

Indeed I am :slight_smile: Are there any developers on your team who worked specifically on this part of PsychoJS who might have some insights? If so, perhaps I can reach out to them. This is probably a topic that would be important for the documentation about the log files, and will benefit the l…

Response Times in Log Files, Key Press vs. Release, and EXP log messages

Online experiments

rkempner January 14, 2021, 2:49pm 11

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Response Times in Log Files, Key Press vs. Release, and EXP log messages

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