In 1968, three marketing professors — James Engel, David Kollat, and Roger Blackwell — published a book called Consumer Behavior and drew a flowchart so ambitious it basically invented a genre. It started with a person realizing they had a problem, then walked them through searching for information, weighing alternatives, making a purchase, and finally evaluating whether they felt good about it. The Engel-Kollat-Blackwell model, EKB for short, became the skeleton of consumer psychology, taught in business schools for half a century. Every funnel chart you’ve ever seen in a marketing deck — AIDA, customer journey maps, growth funnels — is a direct descendant of that 1968 drawing.
🧠 The Five-Step Machine
The model treats a purchase like a factory line running inside your head. Problem recognition: you notice the gap between where you are and where you want to be. Information search: you dig through memory, then the outside world. Evaluation of alternatives: you compare options on function and on feel — which one says the right things about you. Purchase, then outcome: was it worth it, or is that regret already creeping in? Clean, rational, complete. The flowchart was so detailed it looked like the wiring diagram of a spaceship.
🤔 The Consumer Who Doesn’t Exist
Here’s the joke. The model describes a careful, deliberate shopper — and that shopper is almost fictional. Even the EKB authors admitted it: the full five steps only happen in what they called “extensive problem solving,” the high-stakes purchases like houses, cars, or anything socially visible. For the other two categories — “limited” and “routinised” — the brain cuts corners. That carton of milk, that same shampoo you’ve bought for years, that snack at the register: none of it passes through five stages. Most everyday buying is habitual or impulsive. The famous flowchart turned out to be a map of a rare event. You think you’re deciding; most of the time you’re on autopilot.
🔗 Where Advertising Actually Works
This reframes what advertising is for. The model’s first box, problem recognition, has a special entry point: “marketer-induced” recognition — the ad that convinces you that you have a problem you didn’t know you had. That’s where most advertising fights its battle, not at the evaluation stage. It also explains why product pages should look different depending on the stakes. A high-involvement purchase — expensive, uncertain, trust-dependent, like a reading that claims to explain your life — sends people hunting for information and comparisons, so thick proof (samples, transparent process, real examples) beats clever slogans. A low-stakes impulse item needs the opposite: zero friction, one tap, done. Same model, opposite design.
🎲 The Professor Who Modeled God
James Engel’s second act is the strangest plot twist in marketing history. He left consumer behavior behind, took a post at Wheaton College Graduate School as director of the Billy Graham graduate program in communications, and built what missionaries still call the Engel Scale: a numbered ladder from -8 (knows a god exists, never heard the gospel) up to +5 (mature disciple). Look at the rungs — personal problem recognition at -3, decision to act at -2, post-decision evaluation at +1 — and you’ll see the EKB flowchart transplanted onto the journey of faith. He studied how people buy things, then studied how people believe in God, using the same funnel. And in a final symmetry, the Engel Scale got criticized for being too linear — the exact same critique his consumer model had received for decades. He died in 2016, having modeled both the purchase and the prayer with the same five boxes.