I discovered I was a psychopath after taking an online test that predicted personality traits based on one's preference in coffee. While laughing at the result, consider this: How ridiculous are the standardised tests, written and unwritten, that we use to judge our potential and success in life?

The test is Cosmopolitan magazine's Quiz: What Your Go-To Drink Says About Your Personality.

The results page led me to a study last year in the journal Appetite, titled Individual Differences In Bitter Taste Preferences Are Associated With Antisocial Personality Traits.

Researchers from the University of Innsbruck studied nearly 1,000 people and "confirmed the hypothesis that bitter taste preferences are positively associated with malevolent personality traits, with the most robust relation to everyday sadism and psychopathy".

That's it for me, isn't it? Science and a standardised test have spoken. Let's ignore the subjective evidence of the new bottle of mineral water on my desk. An elderly stranger in a wheelchair gave it to me after I helped him in a cafe. ("Uncle, no need." "No, must give you something.")

Standardised tests are an easy way to classify large groups of people, ostensibly to help them achieve their full potential. The PSLE in Singapore and the Scholastic Assessment Test in the United States aim to identify talented students who can be sent to the best schools. The Myers-Briggs personality tests are a favoured tool for adults unsure of what career might suit them.

I did my share of standardised tests as a teen. Every score pointed to my aptitude for the sciences. I should be a doctor, engineer or a lab researcher - a career I tried for a time.

Every friend and relative pointed out my love of text and the arts. I just marked 10 years at The Straits Times, in a career no test suggested I prepare for. (Though my science education did teach me to gather information, analyse it and present my arguments logically, which are essential skills in the newsroom.)

Do standardised tests help or hinder potential? People can limit themselves or be limited in their choices because of test results. Yet the real problem is often not the test-taker but her environment.

Every three years, countries can make 15-year-olds do the Programme for International Student Assessment (Pisa) tests of reading, maths and science.

Singapore topped the last one in 2015, which is a satisfying achievement. But the true value of Pisa is to show how an educational system can be refined or reformed.

Around the world and especially in Singapore, a child's performance in the Pisa test is affected by family finances. The better off the family, the more likely the child is to do well. If a family can afford extra tuition classes and to buy stacks of assessment books, the child will do better in Singapore than a child from a family where these things are unaffordable.

Similarly, where Finland and its comparable population once topped the Pisa tests, student performance is sliding as income inequality grows.

A book published last year by British teacher Lucy Crehan, Cleverlands (Unbound Press), extols Singapore, calling it "a system that ensures all its young people graduate with useful skills". She also points out the problems in a system where youth of differing abilities are separated as early as 12.

Cleverlands cites research showing that separating children of different abilities early is harmful for those who are late to develop or need extra help. Research also shows that delaying streaming has negligible effects on high scorers.

And how are we streaming children anyway? Written tests measure a particular kind of thinking skill, namely the ability to glean information from text and then to communicate this in text.

Consider a favourite PSLE science question about students at East Coast Park who forgot their water bottles. The answer involves the fictional students purifying seawater by digging a hole in the beach, covering it with plastic and collecting pure water from the condensate.

In reality, though, smart students should use the plastic to collect drinking water from the many taps available at showering stations and washrooms along the park. I would love to know which answer would actually get top marks.

In Singapore, PSLE scores seem to start a child on one path in life. Research has shown that labels and social expectations make for self-fulfilling prophecies in the classroom. A study in 1968 and a similar one in 2005 showed that teachers, told that their students are toppers, end up with high achievers in the classroom - even if the students weren't that good to start with.

I've experienced this. I enjoy showing people young and old what fun reading can be. Two eight-year-olds I worked with are dyslexic. They reversed 'd' and 'b'. They hated writing because they couldn't do it as well as their peers

So we started out with picture books, from simple stories to comic books. Six months in, they were doing crossword puzzles and reading books suitable for 11-year-olds - and well too. They even did book reports.

Another "special needs" child couldn't keep up with schoolwork a so-called "normal" child of his age could do. That was what I was told. What I noticed was that he knew what scuba gear did - and explained it to me in simple but accurate terms - even if he couldn't pronounce the words "scuba gear".

Speech therapy and basic reading lessons have improved his literacy and self-esteem remarkably. His true calling might be in social service or as a special needs educator some day. He attracts flocks of children his age or younger, who love his sunny personality and how he uses his growing vocabulary to read stories with them or play word games.

There are of course those who will never be able to read or do maths at an advanced level. And I will never be able to act well enough to make a living at it or sing beautifully enough to fill an auditorium.

Craftsmanship, design sense, theatrical ability and other such skills deserve as much recognition as a Master of Business Administration from Stanford. I invite readers to visit the handicrafts store at Ng Teng Fong General Hospital, where people with special needs have created staggeringly beautiful quilts. Or perhaps a performance by Very Special Theatrics, an inclusive theatre group where some actors have special needs. Mentor R. Chandran insists we hold his troupe to the same standards as any other, he is that confident of its performance.

Standardised tests measure only certain kinds of potential, just as the standardised markers of success in the adult world are laughable in context. Are the marks of success these 5Cs: cash, car, condo, club, credit card? I prefer creativity, consideration for others, cultural intelligence and credibility.

Especially credibility, given the last standardised test I took. Just because I like my coffee black does not mean I won't give my seat at the cafe to a stranger in need.