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
- ↓ practice.jsonThe builder file this video starts from (the end of the previous video).
- ↓ parameters.jsonThe builder file at the end of this video. The next video starts from it.
The lab.js builder: a reaction-time task, step by step
Global parameters
4:03 · narrated, with subtitles in 12 languages · recorded in November 2026
Every number and every text of the reaction-time task moves into one table of parameters, on a sequence around the task. Timeouts, keys, loop sizes and wording read the table through placeholders, and on Open Lab it becomes the fields under Edit parameters.