Marketing Psychology: Evidence-Graded Behavioural Science

Overview

Popular lists of "biases that sell" mix findings that have survived large replications with others that have collapsed, and present all of them as laws. This skill works the other way round: start from a specific decision a customer is not making, find the barrier, choose at most two mechanisms whose evidence holds up, check that the application is honest and lawful, and test it with enough traffic to learn something.

Effect sizes from laboratories shrink in the field. Across 126 trials run by two government nudge units the average effect was 1.4 percentage points, against 8.7 in published academic papers (DellaVigna & Linos, 2022). Plan for small, real gains.

Instructions

1. Pin down the decision

Read the page template, pricing configuration, checkout flow or email in the project, and the analytics for it. Then state, in one line each: who decides, at which moment, what they do now, what you want instead, the current rate, and monthly traffic at that step. If any of these is unknown, get it before proposing a mechanism.

2. Find the barrier from evidence

Use session recordings, support tickets, on-page survey answers and funnel data, not a catalogue of biases. Typical barriers and the mechanisms that address them: