In regard to this article :
http://edition.cnn.com/2015/10/05/asia/singapore-smartest-kids/index.html
Many people think Singaporeans are only exam-smart because they blindly memorize and regurgitate. While that may apply somewhat to lower levels (eg. PSLE and O levels), it doesn't apply so much to higher levels, eg. A levels*, Olympiads, University levels. And at all levels, standards continue to increase and bell-curves continue to be steeper, due to increasing competition for academic qualifications and jobs, both intra-nationally and inter-nationally in an increasingly globalized context.
*Singapore A levels are, by some standards and for some subjects, already more difficult than international A levels.
In short, it is overly simplistic and wrong to say Singapore students are exam-smart merely because they blindly memorize. Blind memorization alone is increasingly insufficient for A level papers (eg. H2 Chemistry), and absolutely insufficient for Olympiads and international competitions.
If Singaporeans always top the international rankings in mathematics and science, and are truly intelligent instead of blindly memorizing and regurgitation, why then (critics love to use this argument), has Singapore produced no Nobel prize winners?
One major reason (there are others of course), which appears to have been overlooked by almost everyone else discussing this issue, is the exceedingly pragmatic Singaporean culture when it comes to money and career. (This holds true for other countries around the world as well, but especially for Singapore where costs of living continue to escalate amidst increasing competition from foreign talent and rising rentals by greedy REITS, even as the Sing dollar strengthens against other regional currencies... obviously there are unethical parties, organizations and industries covertly exploiting this, which is where all the money disappears to instead of benefiting the population... but that's the topic for another discussion altogether).
Whilst ideally (and arguably), the most brilliant minds in any population should work and contribute to mankind's scientific advancement, but here in Singapore, other than Medicine, almost all the top students (who could have qualified for scientific careers) prefer the hugely more financially lucrative careers of banking and finance, law and other careers more profitable than in Science. The kiasu-ism and kiasi-ism, fear of not earning enough to survive or provide comfortably for your future family in increasingly competitive Singapore, coupled relentless societal pressure (eg. Hollywood glamorized Wall Street financial exploits, the proliferation of Top 10 Richest in Singapore / Asia / the World on the internet and social media), motivates one's greed to be the elite cream of the crop, the top 5% elite stratum of society right at the of society, in this dog-eat-dog, survival of the fittest, rapidly globalizing Singapore.
In short, this is one of the very real, major reasons, one that has been mostly overlooked and missed, why Singapore hasn't produced a Nobel prize winner. Not that there aren't any Singaporeans intelligent enough to do so, but that most Singaporeans strongly prioritize financial security and career stability over a PhD research career in the Sciences, which pays out a mere pittance of a fraction compared to careers in banking and finance.
Banking and finance doesn't contribute anywhere as much benefit to mankind, as compared to science, medicine and technology; but it's where the money is, and therefore it's where most of the top brains, minds and students in Singapore, choose to go.