21.5 Modelling Affective State
When recommending to a group of people, you cannot give everybody what they like all of the time. However, you do not want anybody to get too dissatisfied. For instance, in a shop it would be bad if a customer were to leave and never come back, because they really cannot stand the background music. Many shops currently opt to play music that nobody really hates, but most people not love either. This may prevent loosing customers, but would not result in increasing sales. An ideal shop would adapt the music to the customers in hearing range in such a way that they get songs they really like most of the time (increasing the likelihood of sales and returns to the shop). To achieve this, it is unavoidable that customers will occasionally get songs they hate, but this should happen at a moment when they can cope with it (e.g. when being in a good mood because they loved the previous songs). Therefore, it is important to monitor continuously how satisfied each group member is. Of course, it would put an unacceptable burden on the customers if they had to rate their satisfaction (on music, advertisements etc) all the time. Similarly, measuring this satisfaction via sensors (such as heart rate monitors or facial expression recognizers) is not yet an option, as they tend to be too intrusive, inaccurate or expensive. So, we propose to model group members’ satisfaction; predicting it based on what we know about their likes and dislikes.