There is a growing unease, articulated in books, articles and anxious conversations, that something has happened to our collective ability to concentrate. Many people report that they can no longer read a long book with the ease they once did, that their minds wander within minutes, and that they reach compulsively for their phones in any moment of stillness. Whether this represents a genuine, measurable decline or merely a familiar nostalgia for an idealised past is a question worth examining carefully, for the answer has considerable implications.

The case for concern is not without foundation. The technologies that now dominate our waking hours were, in many instances, deliberately engineered to capture and hold our attention for as long as possible. The business models of numerous companies depend, quite literally, on maximising the time we spend looking at screens, and vast resources have been devoted to making their products as compelling u2013 critics would say as addictive u2013 as possible. Seen in this light, the fragmentation of our attention is not an unfortunate accident but the predictable result of a system working exactly as intended.

Sceptics, however, urge caution. Every new communication technology in history, they note, from the printing press to the television, has provoked warnings that it would corrupt the mind and erode the intellectual capacities of the young. Such fears have a habit of appearing overblown in retrospect. Moreover, they point out, the scientific evidence for a genuine, lasting decline in human attention spans is more ambiguous than the alarming headlines suggest. What looks like an inability to concentrate may sometimes be a rational adaptation to an environment saturated with information, in which the skill of filtering and moving quickly between sources is itself valuable.

There is force in both positions, and the truth, as so often, is unlikely to be simple. It may be that our capacity for sustained, deep attention u2013 the kind required to read a difficult text or master a complex skill u2013 is indeed under pressure, while other cognitive abilities are simultaneously being sharpened. If so, the relevant question is not whether we are becoming more or less intelligent in some general sense, but which particular capacities we are cultivating and which we are allowing to wither.

What seems difficult to deny is that attention, however we measure it, is a finite and precious resource, and that the competition for it has never been more intense. If the ability to direct one’s own attention deliberately u2013 to choose what to think about, and for how long u2013 is a foundation of both individual autonomy and serious thought, then its quiet erosion is not a trivial matter. One need not accept every alarmist claim to recognise that learning to protect our attention, in an age designed to fragment it, may be among the more important skills a person can now acquire. The stakes, in the end, are nothing less than the quality of our own minds.