Here's what science says about how digital technology REALLY affects our brains

Look around: Chances are, you'll see someone on their smartphone, computer or other digital device.

Experts are divided on the impacts all this screen-time is having on our brains.

Some people claim that use of the internet, social media, and computer games is having a negative impact on social interaction, empathy, and even personal identity.

But the research doesn't totally support these views, other scientists say.

Susan Greenfield, a neurobiologist at the University of Oxford, in England who mainly studies Parkinson's and Alzheimer's disease, has been outspoken about the dangers of internet use and video games. But critics say Greenfield's views have no basis in the scientific literature.

"...we are concerned that Greenfield's claims are not based on a fair scientific appraisal of the evidence, often confuse correlation for causation, give undue weight to anecdote and poor quality studies, and are misleading to parents and the public at large," Vaughan Bell, a psychology professor at University College London; Dorothy Bishop, a developmental neuropsychologist at Oxford; and Andrew Przybylski, an internet researcher also at Oxford, wrote in an editorial in the British Medical Journal.

Regarding the claim that social media makes kids less social, children's use of social networking sites has actually been found to "enhance existing friendships," these researchers say, "although some individuals benefit more than others."

Studies suggest that people who use social media to avoid social situations report lower well being, whereas those who use it to overcome social challenges are benefited by it.

Greenfield has also claimed that internet-based interactions may trigger autism, which the BMJ researchers say has no scientific backing. Autism is a developmental brain disorder that can be diagnosed in preschoolers. "Her claims are misleading to the public, unhelpful to parents, and potentially stigmatizing to people with autism," they wrote.

Another claim Greenfield and others have made is that playing video games makes people impulsive and aggressive, and gives them a shorter attention span. In fact, some research suggests that playing action video games can lead to a small improvement in mental performance, though more studies are needed.

There's a lot of debate over the link between violence and video games. Some studies suggest violent games can cause a small and temporary uptick in aggressive thoughts and behavior, though others have called this research into question.

Greenfield has also made the claim that the availability of so much information online could lead to more superficial modes of thinking, instead of deep understanding. And the evidence does show that people don't remember things as well when they know they can just look it up online.

As the researchers in this recent review study point out, "In terms of information processing, we are shifting toward a shallow mode of learning characterized by quick scanning, reduced contemplation, and memory consolidation." But this is not necessarily a bad thing, they said, because it means we can free up mental resources for other tasks.

Also, outsourcing our memory to something or someone else is nothing new. We've been doing it for centuries with the written word, or when we're in groups of other people.

Although the cognitive effects of internet use and gaming may be overblown, the physical effects of all that screen time are very real. Spending so much time online is making kids more sedentary, leading to obesity and related health problems. And excessive video gaming can cut into studying time, causing problems at school. (Internet addiction is recognized as a disorder in China, but not in the US.)

Of course, the internet also has many benefits. Families and friends can connect with one another across the world, people everywhere have access to information and educational materials they might never have otherwise, and workers in some industries can work from anywhere with an internet connection.

As Bell and her colleagues say, "we need to recognize that use of the internet and digital technology has cognitive and social benefits and to balance these against any risks."