When Karl Marx published the first volume of Capital in 1867, some readers wondered why he was telling his German audience about the horrors of English capitalism. His reply was that the more developed country showed the less developed country the image of its future. Today, the US offers commentators on the UK government's plans for ÖйúAƬ an image of what is to be hoped, or feared, after the introduction of the new tuition fees regime in 2012.

Anyone looking for signs and portents might turn aside from money for a moment and contemplate a less frequently asked question. When students have had whatever ÖйúAƬ they get, what have they learned? We are familiar with employers complaining that new recruits can't write or speak coherently, lack analytical skills and are unsuited for employment, but it is tempting to put such complaints down to human frailty. Employers have always hoped that someone else would create a productive, uncomplaining, ambitious but biddable workforce at no cost to employers.

Some recent US research suggests that the employers have a case. In 2005, Derek Bok, formerly president of Harvard University, published Our Underachieving Colleges: A Candid Look at How Much Students Learn and Why They Should Be Learning More. He sided with employers at least to the extent of telling his ex-colleagues they could do a lot better. Now the cat has really been set among the pigeons by Academically Adrift: Limited Learning on College Campuses. Its authors, Richard Arum and Josipa Roksa, lack Bok's literary flair, but the artlessness of their report on how little many students get out of ÖйúAƬ makes their work all the more painful. It is a melancholy lament by scholars who think their institutions are short-changing undergraduates.

It's possible - indeed likely - that university administrators will shrug it off with the usual response - "it's not true, and anyway we know it already." But it's just possible that it will have more impact. The research that Academically Adrift draws on doesn't measure what students have learned about specialist subjects; employers are rarely interested in whether their employees have mastered the finer points of Attic verse. What it measures are the skills that are supposed to distinguish college graduates from high school students, that is, the high-level analytical and expository skills whose mastery stands us in good stead regardless of occupation.

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The test that yields these gloomy findings sounds remarkably like the sort of general paper that Oxbridge used to administer in entrance examinations. It's called the Collegiate Learning Assessment, and consists of a couple of writing tasks and a non-technical problem-solving exercise that requires students to analyse messy evidence and make recommendations to an imaginary boss. Many students get no better at this sort of task between leaving high school and leaving university; more depressingly, the gap between those who improve and those who do not widens during ÖйúAƬ. The test tracks differences between institutions and different courses within the same institution.

Anyone suggesting that students don't get what is distinctively "higher" about ÖйúAƬ is vulnerable to accusations of nostalgia for a vanished world, snobbery and historical amnesia. But dig out the numbers from 40, 30 and 20 years ago. The evidence is that students spend a lot less time engaged in academic and academic-related activity now than 40 years ago: a 40-hour week has become a 29-hour week.

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Many students are surprised that they have to work so much less hard than they did in high school. They have to write less, and they are asked to read less. Mastery of the high-level analytical and expository skills that the CLA measures correlates, unsurprisingly, with the amount of reading and writing that students have to do in their particular ÖйúAƬ setting. When they are asked to do a lot less of it than before, the consequences are what you'd expect.

As to why the change has happened, the answers are familiar. There is the fecklessness of students who - anecdotally - choose their courses on the basis of how easy it is to get an acceptable grade on minimal effort. Like the customers of fast food chains, they do it while knowing it's bad for their long-term prospects, and cross their fingers that they will nonetheless be all right in the end.

Why do their teachers let them do it? There is plenty of evidence that many academics have conspired with their students: the faculty won't drive the students too hard, and the students will give the faculty good evaluations in exchange for easy grading. Why might faculty do that? For the untenured, good evaluations are crucial; for the tenured, there are few rewards for being a good teacher in all but the liberal arts colleges, and those few universities that care sufficiently about teaching, or are frightened enough of their alumni.

The ultimately depressing thought is that this is one more obstacle to meaningful efforts to promote social mobility. Students whose parents have degrees learn more, as do students from rigorous high school programmes. Unto those that have, their teachers can give more, and those that have much are more likely to want more. Those that need it most have least idea of what they need, and are the most likely to be distracted, either by the demands of earning money to pay their living expenses, or by the pleasures of social life. Even if they did know what they were missing, they'd be hard-pressed to put in the hard work of reading and writing that is needed.

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Is this confined to the US?