In one version of the test, sound plays immediately as the video begins, if you have sound enabled on your device. Another group is able to turn sound on during the test session using an icon that will sit to the bottom right of videos.The test is interesting given that Facebook's own research concluded that mobile users prefer having the choice to opt in to sound, with 80% of people reacting negatively towards both the platform and advertiser if sound is unexpectedly played. But, given that Facebook is an advertising-driven company with aspirations of pushing deeper into video content, autoplay sound may eventually be a necessary evil.
Both groups see a pop-up message informing them about how to use the controls, and sound will only play if the smartphone's volume is up. If you don't want to annoy your workmates, sound can also be turned to "always off" in Facebook settings.
If you're new to AirPods, considering buying a pair, or just want to pick up some new tips.