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The impact of emotions on decision-making… what if pupillometry could provide a clearer vision?

A CIFRE thesis project at the CSGA, carried out in partnership with Pernod Ricard, has explored the potential offered by measuring pupil diameter in order to quantify the emotions experienced during tasting sessions.  In the longer term, evaluating the impact of emotions on decision-making may also offer industry a clearer understanding of consumer behaviour.

Impact of emotions on decision making ... and if pupillometry helped to see more clearly ?. © Fotolia, Jürgen Fälchle
Updated on 05/13/2015
Published on 03/10/2015

"Let's not forget that the little emotions are the great captain of our lives and we obey them without realising it." Vincent Van Gogh

There is clearly a link between the emotions and eating.  Indeed, our emotions have a considerable influence on our perception of foods. Every day, we take more than two hundred decisions about our food, 90% of which are unconscious, in reaction to contextual variables.  Thus, in order to better understand consumer behaviour, it has become essential to understand our emotions and the fundamental role they play in decision-making.

Emotions that are difficult to quantify

In consumer science, emotions are classically evaluated using a questionnaire, but this measurement remains subjective and limited; indeed, it is not always easy to find words to express them.  This thesis project undertaken in the Centre for Taste, Food and Nutrition Sciences (CSGA) aimed to use pupillometry to develop an objective method to quantify emotions which was adapted to tasting sessions.

Pupillometry - or the measurement of pupil diameters - enables quantification of the dilatation-contraction of the pupil.  It is a physiological measurement that has been used for many years in psychology, and studies have shown that pupil size varies as a function of not only the cognitive load but also the emotional load or preferences.  But very few studies have focused on the relationship between pupil diameter and olfactory or gustatory stimuli. 

Development of a standard procedure for pupillometric analysis

An eye-tracker was used to record movements of the pupil using two infrared cameras associated with a data acquisition software program.  A methodology adapted to tasting sessions was developed, and a certain number of recommendations formulated regarding both the acquisition and processing of data which would be of assistance in the initiation of a pupillometric study.

Application in the field of alcoholic beverages

Experience acquired in a variety of tasting situations has shown that different elements of the dietary context exert a variety of emotional effects.  In particular, odours such as those of alcoholic beverages are strong emotional vectors, as are auditory stimuli when they directly affect the subject (e.g. preferred music).  Thus different assessments have been recorded relative to the same product under different emotional conditions.
In other words, emotions can have an impact on hedonic appreciation.  This thesis project has confirmed the impact of emotional states on decision-making.  It is possible to imagine that, in the longer term, pupillometry could offer a method to predict this impact, particularly if it is coupled with other methods for emotional assessment (such as questionnaires).

Scientific contact(s):

  • Pascal Schlich Centre for Taste, Food and Nutrition Sciences (CSGA)-INRA-21000 Dijon
author of the thesis:
Anaïs Lemercier
Associated Division(s):
Nutrition, Chemical Food Safety and Consumer Behaviour
Associated Centre(s):