More than 80% of children aged ten to 12 in the UK own a smartphone, according to a recent report by media watchdog Ofcom. Many people think this is a bad thing: there has been much debate about whether children should be allowed to have smartphones.

The discussions around the potential negative aspects of children’s smartphone use often focus on the possible mental health risks of social media, or how spending too much time glued to a screen rather than in nature or interacting with others might affect children. On the other hand, smartphones may help children stay connected and interact with supportive communities.

But there’s another aspect to this debate: information overload.

My research is in the science of information. Here we encounter one of the most fundamental laws of nature, commonly known as the second law of thermodynamics. It says that over time, order is replaced by disorder, and information is overshadowed by noise.

To understand this idea in the context of messaging, think of the development of communication facilities. A long time ago, when it was difficult to disseminate information – mainly through handwritten letters that might take months to arrive – people would do so only if the information was of importance.

You wouldn’t expect a friend living a thousand miles away to inform you that their dog had just barked at a neighbour’s cat if it meant that missive would physically have to make a journey of a thousand miles.

Printing, wire communications, the internet and mobile devices have changed this. With each innovation that eases communication, the quality of information that is transmitted reduces.

Nowadays, much of the information surrounding us is noise. By noise, I mean insignificant and irrelevant information that no one needs to know. Nowadays, we know not only that our friend’s neighbour’s cat has been antagonising a dog, but about the lives of the cats and dogs of countless internet acquaintances and strangers.

Increasing noise contamination is a consequence of the law of nature that cannot be beaten easily, if at all. That said, with concerted efforts, sometimes the effect can be reversed momentarily.

Measuring information content

If irrelevant and insignificant information is “noise”, we can – using the terminology of communication theory – call information of interest the “signal”.

Imagine a child wanting to look up specific information on a smartphone for a school project – one of the planets in the Solar System, perhaps. The webpage they end up on contains a huge amount of unrelated information – reader comments, links to other content, maybe advertisements or videos. To reach the knowledge they are looking for, they will have to wade through, and end up absorbing, a huge amount of unnecessary information.

You can think of the proportion of relevant versus irrelevant or incorrect information as the signal-to-noise ratio. A calculation shows that typically, if the noise level doubles, you will have to consume about twice the amount of information to obtain the same level of relevant knowledge. That amounts to doubling your screen time.

So, if the noise level were to grow exponentially, as is inevitable from the second law, then you’ll have to consume exponentially more messages to get the same amount of relevant information. You’ll have to be glued to your smartphone 24-7. This is obviously something we want to avoid – for us and our children.

To make matters worse, the information we consume will affect what we consume next, and information overload can negatively affect this process. When this happens, it becomes all too easy to end up hopping from one site to another without gathering any useful information.

So is there a way out? Well, the answer, in theory, is simple. We just have to keep the level of noise low.

Biological systems in natural environments – that is, without human intervention – tend to maintain stable communication without increasing noise level very much. This is because the methods of communication between animals, typically through sound, olfactory, or visual signals, or between green plants, typically through volatile organic compounds, have hardly changed for thousands of years. Only humans are capable of advancing technologies that significantly increase confusion.

Limiting children’s access to these technologies means their environment becomes a lot less noisy and more calm. The same, of course, applies to adults. An outright ban on smartphones for children is impractical and possibly unhelpful – but creating an environment in which parents can comfortably say “no” to a smartphone, or alternatively in which parents can have an open and transparent dialogue with their children on their smartphone use, might work better.