Subtitles on: why we read almost everything we watch

It isn't just for films in their original language anymore. A series in your own language, a video a few seconds long, a cooking tutorial: the text is there at the bottom, and switching it off almost feels like something is missing. Subtitles have gone from an option to a default setting, often without your remembering you ever turned them on.

Watching where sound can't follow

The first reason is very concrete: a lot of what we watch gets watched in places where sound doesn't travel. On the bus without headphones, in class, in a shared room while someone sleeps, or simply in a feed that starts playing on its own with no sound. Without text, those videos would be unusable; with it, they still make sense. Then there are the lines you don't catch on the fly - a reply thrown out too fast, an accent you don't know well, music covering the voice. Rather than rewinding, you put the text up once and for all.

An accessibility tool that became a shared comfort

It's worth remembering where the setting comes from: subtitles exist first of all for deaf and hard-of-hearing people, and it's that work which made the feature available everywhere. The rest of the world took it up for other reasons - learning a language by reading what you hear, catching a name or an unfamiliar word, following a technical explanation without replaying it. There's a quieter effect too: reading while listening leaves the mind less room to wander off. Plenty of people keep the text on not to hear better, but to stay hooked.

The price: the image comes second

The downside shows up as soon as you pay attention to it: when the text is there, the eye goes and reads it. You stare at the bottom of the screen rather than the face of the person speaking, and you miss what's happening in a look or in a background. Worse, the text sometimes arrives before the line and wrecks a punchline by giving it away just before it lands. And that's before automatic captions, which regularly get names and rare words wrong, to the point of writing the opposite of what was said. So the good habit is the same as for playback speed: keep the text when it makes watching possible, and take it off for the things you actually chose to watch.