Let me start with a simple question — when was the last time you deliberately clicked a banner ad? And if you remember that occasion, what brand or product was it for? Take your time, I have all day.

Certainly, says Angela Seits, managing director of strategy and insights at PMG. And Seits has the brain scans to prove it – or at least, bods at neuro-marketing agency Neuro-Insight do. “You can ...