Passengers use cellphones to kill time while waiting for their trains in Huaibei Railway Station in Anhui province. Wan Shanchao / Asia News Photo

Smartphones: Are they a dangerous obsession or a productivity booster? The distinction isn't always clear. Gray areas of dependence are all too evident.

Yang Yifan is bionic. In a sense, that is.

"My phone is part of my body," the 19-year-old says."Without it, I lose touch with the outside world."

She carries it in her hand, rather than her bag, when she goes out.

Yang begins her mornings checking social media. She grips the device the rest of the day, playing games, ordering meals and reading online novels.

And much, much more.

The Xiamen University French major says she used to read a book a week in high school. She reads far less since she got her smartphone in college.

Zhihu, China's equivalent of Quora, recently told Yang she'd browsed around 200,000 of its web pages last year.

"It's unbelievable! And the worst part is that I can count the books I read last year on my fingers," she says. "My literacy is suffering. That's terrifying."

More than 695 million Chinese accessed the internet via smartphone last year, the China Internet Network Information Center reports. They accounted for more than 95 percent of the country's web users.

The most frequently used app, WeChat, had 768 million daily users, its annual report says. WeChat users born in the '80s and '90s send an average of 74 messages a day.

While smartphone technology has revolutionized the way we live - arguably, largely for the better - there's a dark side of dependency.

How much do we control these devices? And how much do they control us?

Huazhong Agricultural University student Li Zhaojie didn't realize she was addicted until her parents complained.

"The 19-year-old spent her holiday at home with her face in her phone rather than engaging her parents.

"They weren't happy," she says.

"I feel pretty guilty because I spend less time with them since going to college."

Li uses her cellphone in the dormitory bathroom, forcing her roommates to wait.

She knows it's dangerous to stare at the screen while walking in public but can't help herself.

She always takes a battery pack when she heads out.

"I feel hollow and lost when my battery dies," Li says.

After downloading an app called Offtime, she was shocked to discover she spends about seven hours a day on the device.

Li puts her phone away, puts it in silent mode and takes other measures to cut down her screen time.

But her craving remains potent.

She feels anxious and disappointed in herself.

"I get moody when I find I'm wasting time on my phone rather than studying," she says.

Phone addiction can't be clinically diagnosed like dependency on drugs and alcohol.

Tsinghua University assistant professor of psychology Li Songwei says it's not even real.

"People in their 20s face a lot of pressure their predecessors didn't," he says. "They find reasons to blame themselves for imperfections. Phone addiction becomes a scapegoat.

"Of course, people waste time on their phones. But they also waste time without their phones. Worrying about wasting time is more detrimental than the actual time-wasting."

Yet there's also the risk of social disconnection.

Illustrator Hu Yunyi says her boyfriend's smartphone use is the biggest problem in their relationship.

The avid gamer owns four phones.

"He told me I'm his lover, and the phones are his beloved wives," the 23-year-old complains. She feels ignored and disrespected. He pulls out a phone whenever they're together, whatever they're doing.

"His behavior has pushed me to re-evaluate our relationship," she says.

Games are designed to be addictive, explains Wu Chaoran, former operations manager of the mobile role-playing game Dragonform.

"Companies use strategies like daily login rewards and social-media score-sharing to suck them in."

While smartphones enable us to waste time, they also save it.

Users don't need to travel or line up to get goods and services - shopping, banking, ordering food and the like can be done quickly, with a few finger taps.

And mobile platforms offer a greater varieties of goods and services with more affordable options.

Then, there are gray areas that exist in limbo between productivity and playfulness.

Nankai University student Zhang Xuanshuo posts random thoughts on social media to connect with friends.

"I post when I see something funny," the 22-year-old publishing and editing major says. "I enjoy discussing social issues and sharing jokes."

Beyond that, social media enables her to access information and contact people she otherwise couldn't. She has learned terms and about books by following other social science students and academics.

"This is one of the fastest ways to dive into a new academic area," she says. "It's also much easier and faster to learn through other people's discussions."

Many people Zhang follows on social media have studied abroad. She can learn about the countries they live in through their posts.

"Seeing different people's lives online fulfills my curiosity and enriches my life," she says.

Her path to overseas study became clear through posts by an Nankai alumnus who earned a PhD in the United Kingdom.

Zhang used information she discovered via her smartphone to learn about UK media study programs. It helped her locate specific programs and calculate her chances of enrollment.

She received offers from the prestigious London School of Economics and Political Science this year.

Tan Anlyu, a data engineer at Chinese smartphone-maker Xiaomi Corp, believes phones make life more efficient.

He also points out that a smartphone is also only another tool to kill time.

"People immersed themselves in computers in the PC era," he says. "People fiddle with their phones in the smartphone era. I don't see a huge difference."

Tan warns that smartphone users should beware of leaking personal information.

"When downloading a new app, beware of certain requests like accessing contacts," he says. "It's also important to avoid inserting private information like ID numbers."

Indeed, it's a reminder that addiction isn't the only risk our phones pose.

The question is, given the upsides, are the risks worth taking?

zhangzefeng@chinadaily.com.cn