Video tutorials
Narrated walkthroughs of Open Lab and of building tasks in the lab.js builder. Each has subtitles in 12 languages, chapters and a transcript, the files to follow along directly under the player, and a link to its docs page.
Files for this video
- ↓ loop.jsonThe builder file this video starts from (the end of the previous video).
- ↓ scoring.jsonThe builder file at the end of this video, with the scoring script. The next video starts from it.
The lab.js builder: a reaction-time task, step by step
Scoring responses
3:32 · narrated, with subtitles in 12 languages · recorded in November 2026
A short script marks every trial of the reaction-time task as correct, as a wrong key or as a missed trial, including the trials that time out. The video then reads the scores in the debug tools and explains the data file.
Up nextInstructions and a thank-you screen3:45 →