OM DENNE EPISODE
Your brain is wired to find patterns. That's mostly a good thing... until it's not. This episode breaks down illusory correlation: why your team sees connections that aren't there, and what you can do to stop making decisions based on a handful of vivid moments dressed up as a trend.
Have you ever watched your team make a confident product decision based on a pattern that, when you actually look at the data, barely exists?
Illusory correlation is the bias that turns coincidence into conviction. When two things happen close together -- even just once or twice -- our brains quietly file them as connected. The concept was first identified by psychologist Loren J. Chapman in 1967, who noticed that trained clinical professionals were reporting patient behavior patterns that statistically didn't exist. The problem isn't laziness or bad intent. It's just how human memory works. Rare or distinctive events get stored differently, and when two unusual things co-occur, the brain treats that pairing as meaningful -- even when it's pure chance.
In product and design work, this plays out constantly and in ways that feel completely legitimate. A feature ships and traffic ticks up the next day, so the launch gets the credit -- even though a competitor was down and marketing ran a campaign. Six user interviews produce two mentions of a feature, and suddenly that feature defines the whole persona. A few support tickets from one customer segment, and that segment becomes "a tough audience." The misses get forgotten. The hits stack up. And the team ends up navigating by a pattern that was never really there. This episode breaks down how illusory correlation sneaks into your metrics, your research, and your team dynamics -- and gives you a few concrete habits to start catching it before it shapes your roadmap. Give it a listen.
Topics:
• 02:20 – Personal story: the engineering lead I had all wrong
• 04:29 – What is illusory correlation?
• 04:46 – The origin: Chapman’s 1967 research
• 06:19 – Hamilton & Gifford: how the bias distorts how we see groups
• 07:10 – Kahneman & Tversky: why illusory correlations stick
• 07:50 – How it shows up in your product metrics
• 08:23 – The A/B testing problem
• 09:00 – How it distorts how teams think about people and segments
• 09:26 – How it corrupts user research
• 09:50 – Engineering superstitions and team dynamics
• 10:27 – Why more data isn’t always the fix
• 11:00 – Five habits to fight illusory correlation
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