Beware the fallout from enforcing tighter packaging rules

In 1975, food-and-beverage giant PepsiCo started its legendary marketing campaign in which regular people took a blind taste test and drank from two cups, one filled with Pepsi, the other with Coca Cola, and picked a favourite.

The campaign is still being recreated for fun now, this time updated for the social-media generation. Instead of picking out their preferred drink, fans of either brand are often asked to name what they are drinking. It is harder than thought: An experiment by media company Business Insider with 21 participants found that more than half guessed wrong, even though all said they were confident of naming what they were drinking.

The short, just-for-laughs clip drove home a simple fact: packaging and branding made all the difference. The cola drinkers' loyalties were to the brand, not to the taste of the beverage. The brands obviously know this, because both companies devoted almost US$4 billion, more than a 10th of their gross profit, to ad…