SELFIES, eh? Why do this this self-regarding thing? It’s bad enough looking in a mirror without snapping a picture of your own face.

I did this the other day by mistake on my new smartphone. My features were turned into those of a weirdo you’d cross a busy road to avoid rather than an ordinary middle-aged man with glasses and a pronounced lack of noticeable hair.

A story this morning reports that people who take selfies in London appear glummer than those snapping themselves in other world cities.

Now you have to say that modern life is wonderful if someone can go to all the trouble of making such a comparison. The research to uncover this finding used facial-recognition software to compare the expressions of people who publicly loaded pictures onto Instagram in September.

I can let you into a secret here. I just typed that sentence without having much idea of what Instagram is – as in almost no idea at all. Apparently people use it to share photographs and video clips on social media, so there you go.

It must be another of those modern ways to sieve the minutes and turn them into gone hours. I do haunt the time-frittering corridors of Facebook and often glance at the ever-moving conveyor belt of nothing much that is Twitter. The other day I put a picture of a loaf of bread fresh from the oven on Facebook and a surprising amount of people ‘liked’ it, but for all that I shall keep away from Instagram.

The research discovered that self-captured faces in London were less happy than those on display from Berlin, New York, Sao Paulo and Bangkok. These findings will form part of an exhibition at Somerset House in London later this month. Called Big Data, the show explores “the explosion of social media and asks what it reveals about modern society”, according to The Guardian.

Data scientists, designers and researches are said to have collected 152,462 pictures tagged close to Somerset House over one week, 640 of which were deemed to be selfies. A data designer who helped sift the selfies said the analysis revealed much about different cultures in different cities, and also showed how much people were now obsessed with documenting everything.

This is bewildering but true. Of all the inventions that say something about modern life, the smartphone is surely the most influential. This is partly down to their remarkable computing capabilities, but also the way in which they allow people to depict and direct the story of their own life in the public domain.

You can do almost anything on a smartphone, or so I am given to understand. I have discovered a failing in my phone: it’s only as smart as I am. There are many things I haven’t worked out how to do yet. But worryingly for lovely old ink and newsprint, the crisp screen is a perfectly acceptable way to read the news.

The analysis for the Somerset House exhibition recorded twice as many women as men taking selfies, and also that the average head tilt in a London selfie was 15 degrees compared with 20 degrees elsewhere – and if you can find any use at all for that piece of knowledge, you’re more smartly inclined that I am.

Claire Catterall, director of exhibitions at Somerset House, suggests that Londoners are not miserable but “too cool to smile”. Or maybe someone just told them about house prices in London – or perhaps they look miserable because they are in London and not one of those other cities.

Catterall does make a wider point about the amount of data we willingly put into the public domain online – to the point that we are defined by this data in a way we never were before.

Thanks to our phones, much more is known about us and our habits than was possible in the past. Is that at all worrying? Selfie-evidently so, I’d say. And in confirmation of that concern, I just went down into the kitchen to put my porridge on, and there was an item on the BBC Today programme about how the tax authorities can use information gathered from social media to check if people are paying the right tax.

So if you’re smiling in New York when you should be looking glum in London, best keep it to yourself.