Insight

One Good Month, One Wrong Reason

Marcus·Tuesday, October 20, 2026 Edition

THE STORY THAT STUCK

Fenella Osei closed her laptop at half past ten on a Friday, satisfied in a way she hadn't felt in months. Sales were up thirty percent. She knew exactly why: three weeks earlier she had started sending follow-up emails on the same afternoon as the first call. She'd tested it, seen the numbers climb, and now it was policy. The office plant on her desk had shed two leaves during that same period. She did not credit the plant.

The brain does not record events. It constructs narratives — and a narrative's job is coherence, not accuracy. Two things happen close together, one of them changes, and the mind snaps them into a cause-and-effect pair with the speed of a reflex. This is not stupidity. It kept our ancestors alive in environments where fast pattern-matching mattered more than statistical rigor. The trouble is that the same mechanism runs inside a quarterly review, a relationship debrief, or a career pivot. And there, speed is the enemy of truth.

The brain does not record events. It constructs narratives — and a narrative's job is coherence, not accuracy.

The psychologist Daniel Kahneman documented this precisely in his work on what he called the illusion of understanding — the confident sense that we know why something happened, assembled after the fact from whatever details survived in memory. Stock traders, he found, construct explanations for market moves that feel airtight and are largely post-hoc. The narrative arrives before the analysis and then resists replacement, because a good story is harder to dislodge than a bad hypothesis.

READING LAST MONTH'S RESULTS

Fenella's follow-up emails may have mattered. They may not have. What she skipped was the question she needed to ask the morning after the good month: what else changed? A competitor went quiet that quarter. Two large accounts renewed early. The product team had fixed a friction point in the demo. Each of those shifts moved the same needle. The discipline, when looking back, is to list every change before naming the cause. Not to paralyze the review, but to stop one plausible story from eating all the credit. Write the confounding variables down before you write the lesson.

The lesson you remember most clearly is usually the one with the best story attached, not the one that is most true. Fenella's rule about same-day emails will survive long past its usefulness, because she lived it as a narrative. Your past is full of those rules. Some of them are costing you.

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Try This

Find one decision you made this month based on what worked before. Write down three things that also changed during the period you're drawing that lesson from. If you can't name three, you haven't finished the review.

How?

Key Facts

*When something works, your brain automatically assigns credit to whatever you did differently — but correlation between two events is not evidence that one caused the other.

*Narrative coherence is not the same as accuracy: a story that feels complete and satisfying is often the one that has hidden the most confounding variables.

*Before acting on a lesson you drew from a past outcome, write down at least two other factors that changed at the same time — this interrupts the single-cause story before it hardens into policy.