The best person for the job should always be able to tell you why a tennis ball is fuzzy

In a perfect world of our collective, idealised imaginings, where everything always works, processes run like clockwork, and where Piers Morgan has never been born, job interviews would be simple, straightforward affairs that always produced the best person for the role.

Interviewers would ask normal, reasonable and helpful questions such as ‘why do you want the job?’ and ‘what could you bring to the role?’, designed to elicit clear, relevant and equally helpful responses.

Throughout the process, both parties would exhibit big, beaming smiles, safe in the knowledge that the whole thing would be over in under an hour and they could all be standing in the lunchtime queue at Greggs long before they ran out of steak bakes.

Back in the real world however where Donald Trump could soon be re-elected President of the US – let me repeat that, where Donald Trump could soon be re-elected President of the US – such ideas are considered far too radical and ‘out there’ ever to have a chance of succeeding.

Instead, more and more employers now favour setting conundrums such as ‘why are manhole covers round?’, ‘why are tennis balls fuzzy’ and ‘how many windows are there in London?’.

They do so, one assumes, because they believe the answers to such teasers will be more enlightening than simply by asking, ‘what skill that you have do you think will be important for the role?’.

Such questions originated in Silicon Valley, where bosses of companies at the cutting edge of technology wanted to develop new ways of scrutinising candidates’ thought processes.

The problem is that they now appear to have been adopted by owners and HR leads at smaller, general companies who are motivated more by the sense of power it gives them.

The challenges faced by cutting edge life sciences companies, for example, often have no known solutions and they need to recruit people who can approach problems laterally and are capable of thinking in new and creative ways.

Asking a candidate to estimate how much New York weighs might be a legitimate question if you need a quantum physicist to unlock the inner workings of the hadron, but not if you’re a job agency in Bathgate, looking for a part-time checkout assistant for a local branch of Poundland.

According to a recent study in the journal Applied Psychology, interviewers who use brainteasers are in the position of the game show host who already knows the answers to the questions they are posing.

“People in such a position have been repeatedly shown to overestimate the likelihood that they would have known the answer had they not seen it previously,” the report said.

“Interviewers using brainteasers, therefore, may be motivated by the desire to protect and enhance their self-esteem. They may simply want to show others how smart they are.”

While such questions have been used by major businesses like Microsoft and Facebook as well as Oxford and Cambridge universities, Laszlo Block, a senior vice-president of Google has described them as ‘a complete waste of time’.

One candidate sent to an interview by a Glasgow-based recruitment agency recently was asked at the end of the session what he was planning to have for dinner that evening.

Believing the formal part of the interview to be over and that the interviewer was making polite small talk, he said he was taking his girlfriend out for a meal at a fashionable restaurant.

Only after the candidate had landed the job, was he told the question was part of the interview process.

The business owner interviewing him believed his answer told a lot about the candidate’s personality.

If he’d said he was going to buy a ready meal or a takeaway, it might have suggested he was disorganised, ill-disciplined and that he didn’t take care of himself.

That he was treating his girlfriend to an expensive meal suggested that he was caring, thoughtful and that he demanded quality.

Of course, he might equally have been trying to make up to his girlfriend because he’d just had a menage a trois with her mother and her pet Alsatian. Or he may have felt guilty at having to cancel their wedding, because he’d blown the budget in a lap dancing bar.

The candidate who said he planned to grab a ready meal from the supermarket may not have had time to think about dinner because he’d spent the past six months volunteering in a leper colony in the Central African Republic, before solving Fermat’s last theorem on the back of a fag packet on the flight home.

In the end, the successful candidate lasted only a few months before resigning to set up a rival firm with his girlfriend. His erstwhile boss, he said, was a complete idiot and he planned to put him out of business.