Consider trying to predict the details of unattached people’s kisses. That is, you might have data on who such people have actually kissed when, where, and how, and data on who they say they would be willing to kiss under what circumstances. From such data you make models that predict both the kisses that actually happen and the kisses they say they are willing to join. For example, you may notice that they kiss more when they are awake, are not busy with other activities, and feeling frisky. They kiss more when they and their partner are clean and well groomed. They kiss more when they are more attractive to others, and when other willing partners are more attractive to them according to their preferences.