“Everyone does it.”

These were the words from my college-aged daughter when I caught her lounging on our couch, streaming Friends with 24-point closed captioning on. She has no hearing impairment, and I wanted to know what she was up to.

Does “everyone” do it? My wife and I turned to Facebook and a private, nationwide group for parents with near-adult children. “Anyone else’s college student (without a hearing disability) watch TV with the closed captioning on and insist that everyone does it?” my wife posted. Seven hundred responses (and counting) later, we had our answer.

“It helps me with my ADHD: I can focus on the words, I catch things I missed, and I never have to go back.”

Many parents expressed similar confusion with the TV-watching habits of their millennial and Gen Z children, often followed with, “I thought it was just us.”

I returned to my daughter, who had now switched to the creepy Lifetime import You.

“Why do you have captions on?” I asked.

“It helps me with my ADHD: I can focus on the words, I catch things I missed, and I never have to go back,” she replied. “And I can text while I watch.”

My multitasking daughter used to watch TV while working on her laptop and texting or FaceTiming on her phone. She kept rewinding the DVR to catch the last few minutes she’d missed because she either zoned out or was distracted by another screen.

Her response turned out to be even more insightful than I realized at first. A number of mental health experts I spoke with — and even one study I found — supported the notion that watching with closed captioning serves a valuable role for those who struggle with focus and listening.

“I do see this a lot in my practice,” said Dr. Andrew Kent, an adolescent psychiatrist practicing in New York and Medical Director of New York START, Long Island. “I believe auditory processing is more easily impacted upon by distractions, and that they need to read [captions] to stay focused.”

Closed captioning is a relatively recent development in the history of broadcasting, and it was designed with the hearing impaired in mind. According to a useful history on the National Captioning Institute’s (NCI) website, the technology dates back to the early 1970s, when Julia Child’s The French Chef “made history as the first television program accessible to deaf and hard-of-hearing viewers.” Real-time captioning arrived later, with stenographers typing at a blazing 250 words-per-minute to keep up with live news and sporting events.

They use captions to focus more intently on the content.

If it wasn’t for the Twenty-First Century Communications and Video Accessibility Act of 2010 and additional rules adopted by the FCC in 2012, it’s unlikely my daughter’s IP-based Netflix streaming content would even have closed captioning options today.

While the NCI doesn’t explicitly acknowledge the growing use of closed captioning by those without hearing impairments, it does note that “closed captioning has grown from an experimental service intended only for people who are deaf to a truly global communications service that touches the lives of millions of people every day in vital ways.”

It’s certainly not just a phenomenon for young people. There are many people my age who admit to using them because they have some middle-aged hearing loss or simply need help understanding what the characters on Luther or Peaky Blinders are saying. They use captions to focus more intently on the content.

The need to read captions for what you can hear might even have a biological base. According to Dr. Sudeepta Varma, a psychiatrist at New York University’s Langone Medical Center, some people may have trouble processing the audio from television.

“I believe that there are a number of individuals who have ADHD who may also suffer from undiagnosed auditory processing disorder (APD), and for these individuals… this may be very helpful,” Dr. Varma told me via email. Closed captioning can provide the visual cues that APD sufferers need to overcome their issues with listening and comprehension, she added.

APD refers to how the brain processes auditory information, and though it supposedly only affects around 5 percent of school-age children, there’s reportedly been a significant uptick in overall awareness. As Dr. Varma pointed out, there may be a lot of people who don’t realize they have APD, but are aware of some of the symptoms, which include being bothered by loud noises, difficulty focusing in loud environments, and forgetfulness.

There may be applications in the classroom, too. In a 2015 study of 2,800 college-age students on the impact of closed captioning on video learning, 75 percent of respondents mentioned that they struggle with paying attention in class. “The most common reasons students used captions… was to help them focus,” Dr. Katie Linder, the research director at Oregon State University who led the study, told me.

And even four years ago, there were hints that the use of closed captioning as a focusing tool would bleed outside the classroom.

As a report on the study put it, “Several people in this study also mentioned that they use captions all the time, not just for their learning experience. Captions with Netflix was mentioned multiple times. So, we know that students are engaging with them outside of the classroom.”

When the NCI first co-developed closed captioning technology some 50 years ago, they called it “words worth watching,” and it did transform millions of lives. Today, we may be witnessing — or reading — a similar revolution.