Although every child tries it out, it’s pretty difficult to get a lie past your mammy.

The child’s predicament is neatly reflected in one of my favourite studies in psychology where children were asked the simple question: who knows you best?

Under the age of eleven, most children decided that it is Mum who knows their intentions the best of all. It is only from the age of eleven that they begin to perceive themselves as masters of their own minds. Only then, indeed, do they discover that they can pull off lying and perhaps not be caught out.

Lying, it seems, is the domain of adults. Because we have the ability to see the world from others’ perspectives, we see value in pleasing them by telling them that which they will like.

Much of the time this is no bad thing. White lies are essential buffers. The apotheosis of human civilisation – the city – would be quite impossible without a fair smattering of untruths.

When it comes to brands, lying is a different propositon entirely. Brands are often expected to exaggerate, to distract, to romanticise – even to obfuscate – but consumers will not long tolerate lies. Like many elements in our culture, we are often not aware of where the limits lie, until they are transgressed.

Marketing duplicity found its poster boy in the 1998 launch of Sunny Delight. It sat, big, proud and excited, in the chiller cabinets of Europe.

The initial consumer enthusiasm was electric. I recall retailers proclaiming a new era of better-for-you drinks. Carbonated beverage companies were reported more than a little scared.

Then, the lie was revealed. Clouds descended on the Sunny D party. Worse, the lie, it transpired, sat at the heart of the brand.

Far from being healthy, fresh, delightfully full of oranges, Sunny D emerged as a fraud with too little fruit juice (5%), no need to be chilled, too many additives and – as if to underscore some demonic intent – turned kids’ skin the colour orange. The very reason for buying Sunny Delight became the reason not to buy it.

Which brings me to that chastening tale of near-triumph named Seán Gallagher, independent presidential candidate.

Polling in the Irish presidential election of 2011, two weeks before voting, had Gallagher in the lead. With 40% of first preferences promised to him, his election seemed a near certainty.

Three days before polling, he was accused of having collected money on behalf of Fianna Fail in 2008. Thus, his connections were seen to be close and his commitment deep. The accusation played out on live TV with 900,000 people watching.

Fianna Fail, in government at the time of the fund raising incident in 2008, was seen by many as a failed and corrupted force which participated in the economic demise of the nation. Gallagher – the independent candidate above bickering and negative campaigning – froze, dissembled, mumbled, and could not robustly defend his actions. He was caught in a lie of his own making. His vote, tenuous like most political brands, collapsed.

The act of marketing is not the act of whole-truth telling. Rather, it is the act of best-foot-forward. This is the positive space where brands talk to their relevant advantages and benefits. As consumers, we know that the rules of the game are caveat emptor – buyer beware. The reason we regulate communication to kids so carefully is that they cannot appreciate this fully.

When a brand lies, however, it is as if it itself becomes a ten year old child. The consumer, mammy of the market, will eventually hunt down the lie: expose its evils, and administer appropriate punishment.