Where customer development comes from

From Lewin to the four forces

1936. Kurt Lewin, Principles of Topological Psychology. Behaviour is a function of the person and their environment: B = f(P, E). To understand why a buyer changes, study how their situation changes. That’s why the method starts with the buyer’s situation.

1951. Kurt Lewin, Field Theory in Social Science, his papers collected after his death in 1947 and edited by Dorwin Cartwright. Behaviour only makes sense inside the whole situation around it, which Lewin called the field, and change happens when the forces pushing for it outweigh the forces holding things in place.

1961 onward. René Girard, mimetic desire, read through Wolfgang Palaver’s René Girard’s Mimetic Theory (2013). We desire what others desire. It’s why a reference customer moves the next buyer more than any claim you make about yourself.

1973. William T. Powers, Behavior: The Control of Perception. Goals stack in a hierarchy, from who someone wants to be down to what they do today. In business-to-business sales the goal at the top is usually a profitable business, so the method maps a buyer’s profit engine before their feature list.

1998. Charles Carver and Michael Scheier, On the Self-Regulation of Behavior. People act to close the gap between where they are and where they want to be. That gap is the push a buyer feels.

1997 to 2005. Gerald Berstell and Denise Nitterhouse, Customer Case Research at DePaul University: case studies of real buying situations, including the 2004 working paper on targeting situations over demographics. The situation predicts a purchase better than the buyer’s profile does, and their work carries Lewin’s field into the 2007 jobs paper below, which they co-wrote with Christensen.

2005. Steve Blank, The Four Steps to the Epiphany. Customer development as its own discipline beside product development: customer discovery, customer validation, customer creation, company building.

2007. Clayton Christensen, Scott Anthony, Gerald Berstell and Denise Nitterhouse, “Finding the Right Job for Your Product”, MIT Sloan Management Review, Spring 2007, pages 38 to 47. Customers hire a product to get a job done in a particular situation, which became jobs to be done.

2011. Eric Ries, The Lean Startup. The value hypothesis and the growth hypothesis: will people get value from this, and how will new customers find it?

2013. Bob Moesta and Chris Spiek, the Re-Wired Group, Business of Software. The switching timeline, from the first thought through buying and living with the choice, and the four forces: the push of the situation and the pull of the new solution, against the habit of the present and the anxiety of the new.

Where it shows up in my own work

2016. The Medlantis experiment board, and my talk on it, “The Art of the Pivot”, for the Queen’s Venture Network in Toronto. The full story is on the method page.

2018. My talk on being an intrapreneur put Ries and Blank side by side: the value hypothesis is product-market fit, and the growth hypothesis is channel-market fit.

2020. I pulled on the jobs-to-be-done threads until they led me to the origin story: Denise Nitterhouse’s Customer Case Research, the method I’d been using all along. In April I wrote to thank her and to give her the attribution, and she wrote back the same day.

That year my growth model also defined a growth loop as product-market fit plus channel-market fit plus a referral coefficient.

2026. The same line runs through the go-to-market assumption portfolio and the free kit: start from the buyer’s situation in their own words, rank what you’re assuming, build the proof they need to trust you, then test.

Ninety years of research says people change when their situation pushes harder than their habits and anxieties hold them, and the whole method is built to measure that.