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Automatic facial expression coding offers promising insights into the immediate emotional impacts of calorie labelling

A new study suggests that nutritional information labelling ‘nudges’ may offer some influence in helping people who are less healthy, make healthier choices. For those who are more health-conscious though, calorie labelling offers little influence on making healthy food choices and may cause immediate negative emotions.

We show how calorie labelling can make some people feel quite unhappy – without even changing their behaviour.

Professor Paul Dolan

Can individuals be influenced to make healthier choices simply by the way information, such as calorie labelling, is presented to them? Such behaviourally informed approaches – or “nudges” - have been gaining traction in public policy for the past decade, but little has been understood about the consumer welfare affects that these interventions elicit and the overall impact on consumer choices.

A new exploratory study, conducted by Dr Kate Laffan, Professor Cass R. Sunstein and Professor Paul Dolan in the LSE Behavioural Lab for Teaching and Research, used automatic facial expression coding, via webcams, to investigate the impact that nudges have on people’s choices, and to analyse the emotional impacts caused by the intervention.

107 participants were invited to the Behavioural Lab to be part of a “cinema experience”, involving watching short movie clips of popular films. Before the screening, each participant was offered high-calorie, sweet and salty popcorn. Before choosing to accept the snack, the calorie information was displayed on their screen.

The first part of the study was to assess whether individuals chose to accept the snack. The authors found that, on average, being presented with the nutritional content had no impact on people’s consumption of the popcorn. Individuals chose the popcorn snack despite the seeing the nutritional information on screen. In a subgroup analysis, the authors did find some evidence to suggest this intervention did impact individuals who reported to be less health-conscious to make healthier choices.

The aim of the second part of the study was to capture and analyse time spent in a negative emotional state, using webcams to capture the facial expressions of the participants as they watched the first and then second movie clip. The footage was analysed in the biosensor platform Imotions using the facial expression coding software Affectiva.

Interestingly, the authors found that viewing the calorie information did impact the emotions that participants experienced during the moment of choice, and that this varied depending on their level of health-consciousness. Participants who were more health-conscious, spent more time in a negative emotional state, although this was short-lived.

The authors suggest that these types of intervention may produce emotional costs for the health-conscious, without necessarily producing any health benefits. If well-being is to be prioritised, they suggest that policymakers should do more to measure the welfare costs and the welfare benefits of such interventions.

The authors go on to suggest that software such as Affectiva, enables automatic facial coding to be used quickly and effectively and potentially opens up a new approach for researchers and policymakers to go beyond the question of whether a nudge affects people’s behaviour, and to gain insight into the immediate effects of how they feel because of it.

Lead author Dr Kate Laffan said:

“Automatic facial coding can enhance policymaking by providing insights into how nudges make those people who are subject to them actually feel - an important question that had been largely ignored in research and policy circles to date.”

Co-author Professor Paul Dolan said:

“Behavioural scientists have become pretty smart at nudging people to behave differently but have been remarkably silent on whether those nudges make people happier. We show how calorie labelling can make some people feel quite unhappy – without even changing their behaviour. Our paper is a further reminder that we must always consider the welfare effects of nudges.”

Behind the story

Laffan, K., Sunstein, C., & Dolan, P. (2021). Facing it: Assessing the immediate emotional impacts of calorie labelling using automatic facial coding. Behavioural Public Policy, 1-18. doi:10.1017/bpp.2021.32. Available open access here.