The untapped potential of unobtrusive observation for studying health behaviours

Improving the environment is an important upstream intervention to promote population health by influencing health behaviours such as physical activity, smoking and social distancing. Examples of promising environmental interventions include creating high-quality green spaces, building active transport infrastructure, and implementing urban planning regulation. However, there is little robust evidence to inform policy and decision makers about what kinds of environmental interventions are effective and for which populations. In this viewpoint, we make the case that this evidence gap exists partly because health behaviour research is dominated by obtrusive methods that focus on studying individual behaviour, and which are less suitable for understanding environmental influences. By contrast, unobtrusive observation can assess how behaviour varies in different environmental contexts. It thereby provides valuable data relating to how environments affect the behaviour of populations, which is often more useful knowledge for effectively and equitably tackling population health challenges such as obesity and non-communicable diseases. Yet despite a long history, unobtrusive observation methods are currently underused in health behaviour research. We discuss how developing the use of video technology and automated computer vision techniques can offer a scalable solution for assessing health behaviours, facilitating a more thorough investigation of how environments influence health behaviours. We also reflect on the important ethical challenges associated with unobtrusive observation and use of these emerging video technologies. By increasing the use of unobtrusive observation alongside other methods, we strongly believe this will improve our understanding of the influences of the environment on health behaviours.