This week’s Brainfood is inspired by a recent talk we saw at The Royal Institution: “Passion for Poison: The real science of Agatha Christie”.

Agatha Christie knew her poisons. She worked in a pharmacy during the First World War at a time when some of the deadliest substances imaginable were freely available – a little something unpleasant dropped into the sherry, arrow poison delivered quietly mid-flight into the neck of an unfortunate passenger…

Oddly enough, that’s a bit how marketing works.

We’re not suggesting your marketing strategy should include strychnine, but, rather like Christie’s poisons, the smallest, quietest things often have the greatest impact. These are micro-insights: those tiny, almost indiscernible crumbs in the data that tell you your customers are secretly annoyed about how chummy your AI bot is.

If ignored, micro-insights can prove deadly…

Arsenic and the importance of microscopic moments

Arsenic is an old favourite of Christie’s. It’s odourless, tasteless, and creepily effective – rather like a subtle, insidious dip in brand engagement scores. In market research, a seemingly irrelevant comment — “Their emails are rather long” — might in fact be an arsenic moment. It looks like nothing. Feels like nothing. Until you realise it’s one of the reasons people are switching to an easier-to-deal-with competitor.

Great marketers love the marginalia. They hunt for the odd remark, the unprompted sigh in an interview, the single comment that wasn’t asked for and no one else clocked. Because the body isn’t even cold before the CEO asks: “Why didn’t we see this coming?”

Strychnine and the perils of ignoring the obvious

Strychnine, unlike arsenic, makes a bit of a fuss. It convulses, it writhes. It’s a drama queen. Christie used it to great effect in The Mysterious Affair at Styles. But sometimes we unwittingly miss its more obvious warning signs. An irritated response to a creative script, a confused beta group, a weird spike in angry tweets from Finland — it’s all there, blithely ignored until it blows up on launch day. The lesson? Read the room. If someone in the room is twitching slightly and foaming at the mouth (metaphorically speaking), pause before you hit “publish.”

Digitalis and misplaced good intentions

Digitalis, which comes from the foxglove plant, is another Christie classic. In the right dose, it helps your heart. In the wrong one, it stops it. Completely. This is marketing’s equivalent of the well-intentioned personalisation strategy that quickly devolves into full-blown creepiness. You start off trying to help: “Would you like to reorder those vegan lentil crisps you bought last Tuesday at 3:12 p.m.?” And suddenly the customer is deleting your app and filing a complaint with the GDPR hotline.
Micro-insights again signal the early warning signs – the wary pause in a usability test, the mild irritation in the comment section of a loyalty program. It’s so easy for even the most well-intentioned initiatives to misfire in the real world. What’s meant to heal can harm.

So what?

Christie didn’t need gore. Timing, motive, and one impeccably placed clue were everything. Likewise, we don’t need an avalanche of analytics to get to the heart of an audience’s mindset. A microscope and a set of carefully tuned antennae can often take us further.

So ask odd questions. Look for the lonely data point. Channel Poirot, with his fastidious moustache and compulsive suspicion. Because while everyone else is focused on the obvious, you’ll be the one spotting the metaphorical empty bottle of belladonna in the corner.

Agatha Christie taught us that poison works best when no one notices. So do insights. Be subtle. Be curious. And for heaven’s sake, check the tea. Because if history—and Miss Marple—have taught us anything, it’s this: ignore the small stuff, and it might just kill you.

Sarah