Onset/offset times of a trial

Online experiments
1

The goal is to know approximately how much time each participant spent on one trial. I have attached a picture showing the components of this trial (it’s in a loop).

The ending condition is: The Mouse object enabled “End Routine on Press: valid click”. When they click on tone_report_button, this trial ends.

You can see from this timeline, the tone_report_button and the Mouse object will not appear 1.3s into the trial (after stimuli being played, controlled by code component).

Weirdly, the duration of the trial (calculated by trial.end - trial.start) is sometimes smaller than 1.3s. Theoretically, participants can only click on the button after it appears (after 1.3s)?

I also have tried setting up a similar duration measure in code component:
in Begin routine: I have trial_start_time = psychoJS.monotonicClock.getTime();

Then in End routine: I have response_time = psychoJS.monotonicClock.getTime() - trial_start_time;

This value is sometimes lower than 1.3s too.

Could anyone help explain what might have gone wrong here? I’m happy to provide more information. Thank you very much!

Screenshot 2026-03-18 at 14.59.16
Screenshot 2026-03-18 at 14.59.161846×1224 116 KB

OS (e.g. Win10): MacOS
PsychoPy version (e.g. 2024.2.4 Py 3.8): v2025.2.4
Standard Standalone Installation? (y/n) If not then what?: Yes

2

Check the values of t (routine time) and tone_mouse.time.

3

I did not record tone_mouse.time.
Could I ask how to interpret the tone_trial.started and tone_trial.stopped then?

Both tone_trial.stopped -tone_trial.started and response_time (defined above) are sometimes smaller than 1.3s, during which the tone_mouse did not appear and ideally would not trigger end trial condition?