We often have simplistic or preconceived ideas about the preferences of users. We must analyze their behavior if we want design successful products and services.

The Museum MNAC of Barcelona is located in one of the highest parts of the city and to get there visitors must climb a set of stairs. I’ve visited the museum a few times and I’ve always detected a curious behavior that can serve as a lesson for product and service design.

As shown in the figure below, before reaching the museum there are three key moments where visitors must make a choice: climbing the stairs or taking the escalators.

mnac sugoru design

In the first two stages, the option chosen by a majority of visitors is always the same: the escalators. It seems obvious, since it’s the most comfortable system. In the first stage, escalators make it easy to overcome the obstacle of the road and in the second stage there is a steep slope.

However, when we reach the third stage, a change of behavior occurs. A group of people (mostly elderly) continues to use the escalators, while the others choose the stairs. What happened?

There’s a hidden variable.

Up to the third choice, we had assumed that visitors evaluate the different options based on a single variable: comfort. Indeed, the escalators of the first and second stages are the most comfortable options.

In the third stage, escalators remain the most comfortable option, but now we have to make a detour to reach them. Then why do some visitors choose the stairs? Because they are the fastest option. We’ve found the hidden variable: speed.

People have different scale of preferences according to their characteristics. In this case, there’s a group of people who value speed over comfort and there is another group (with reduced mobility) for whom comfort is paramount.

In the first and second stage, the escalators are both the easiest and fastest option. Consequently, this is the option chosen by both groups. We hadn’t detected the second variable (speed) because it was hidden behind the obvious variable (comfort).

In the third stage, the behavior of people changes by simply placing the escalators a little further. This way, now the stairs are the most comfortable option, but the escalators are the fastest one.

This example shows us that in order to design efficient products and services is necessary to know the scale of preferences of our users and detect hidden variables. No matter if our product or service is technically “perfect”. If we don’t understand what really motivates users’ behavior the result could be a disaster.