Every article that answers this question just quotes a study and moves on. The interesting part is that you can reproduce the finding yourself in about two minutes, on your own hardware, with the same finger and the same input chain. I published the full, source-backed version on KeyboardTester.
Source: [Dev.to](https://dev.to/nasirazizawan/do-you-react-faster-to-sound-or-sight-test-both-in-your-browser-33ge)