

Customer In A Store is a short, web-based behavioural simulation designed to examine how individuals interpret dynamic systems involving inflows, outflows, and accumulation over time. Participants act as independent decision-makers who analyse graphical time-series data representing customer entry and exit in a retail store, inferring stock levels visually and identifying moments of maximum and minimum accumulation — without being shown cumulative values explicitly.
The simulation is intentionally designed to surface intuitive but incorrect reasoning rather than to reward technical skill. It highlights two systematic cognitive errors — stock–flow failure and the correlation heuristic — and evaluates the effectiveness of three structured learning interventions in correcting flawed intuition. The pedagogical intent is not to teach formulas, but to confront participants with their own cognitive biases and demonstrate how decomposition and feedback can improve reasoning in dynamic systems.