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University of Bath

Understanding water use in private settings: The case of showers

This project uses descriptive norms to understand the issue of privacy and its effects on normative behaviour in actions with sustainability implications.

Water coming out of a showerhead.
A lot of water use is done in highly private settings, such as bathrooms, which means we might lack information on how others use water.

We know people are often influenced by the behaviour they observe in others – a process called descriptive norms. However, a lot of water use is done in highly private settings, such as bathrooms, which means we might lack information on how others act and so be unable to calibrate our behaviour to what is normal. Bath’s Psychology department carried out studies aiming to test whether this was true, and whether providing people with feedback on how they compared to others could shift their water consumption. The idea of descriptive norms is well established in psychology, but this study is the first specifically to get to grips with the issue of privacy and how this might be a barrier to normative behaviour when it comes to actions with sustainability implications.

Project outline

There were two important aspects to this work. First, we carried out a survey to test our hypothesis that privacy is important. We asked people to rate how private they felt a series of everyday behaviours were – behaviours that ranged from shopping to using the toilet. We then asked another set of people about how they performed each of those behaviours. As expected, we found a correlation between how private a behaviour is and how variably people do it – the more private the act, the more variation there is in how people do it; in contrast, acts that are very public tend to be done much the same by most people. This all fits with the idea that privacy is a barrier to normal descriptive norm processes.

We then carried out a study of shower times in student residences. Using specially constructed data loggers, we recorded the length of people’s showers for a period of weeks. We then gave each person feedback on how the length of their showers compared to the average for the whole group. Critically, we actually gave the feedback at random, so each participant had an equal chance of being told they were above or below average.

We found, as expected, that the feedback tended to make people shift their behaviour to become more like the norm. People who were told their showers were above average started to take shorter showers. Unfortunately, we also found that people who were told they were below average started to take longer and use more water! But even though this is an undesirable outcome, it still fits with the idea that people generally calibrate their behaviour to what is seen as normal, and that it is privacy that stops them doing this in many water-use contexts.


This work is relevant for a whole range of sustainability behaviours. Being able to influence consumption through normative processes has the potential to influence a broad range of real-world activities.

This was the PhD project of Elaine Gallagher from the Department of Psychology.