I tend to enjoy myself quite a lot when I swim. And yet, I would very rarely choose to swim when the opportunity was available. One might conclude from this that though I liked to swim, I didn’t want to swim, so my “wanting” and “liking” were out of sync. But on further reflection, something more subtle was occurring. When I would try to decide whether I wanted to go for a swim, I would do so by performing a quick mental simulation of the experience. The problem was, that in the case of swimming, the snippet of the experience that would come to mind when I would consider swimming was the moment I jumped into the pool. I would imagine the sudden shock of the cold water hitting my skin, which I find to be an unpleasant experience. So when I would say, “I don’t want to swim now”, what was really going on is that my mental model of swimming that came to mind was not a pleasant one.
This way of deciding between options is quite common. When someone asks us whether we want an apple or an orange, we often will imagine what the experience of each is like, and see which simulated experience feels the most positive. So sometimes when we say that we “want” something, what we mean is that when we imagine that thing it produces a positive experience.
Perhaps it was no coincidence that my memory of swimming involved the peak intensity of the experience (jumping into the cold water was a more intense experience for me than any other aspect of swimming). There is a rule of thumb known as the peak-end rule which says that we base our judgement of how good or bad experiences are mostly on their peak intensity and the way that they end. So if an experience is quite pleasant on average but contains a few seconds of very negative experience and ends poorly, we are likely to view that experience after the fact as having been unpleasant. For swimming, not only is the peak intensity rather unpleasant for me, but the ending is as well. It often involves walking around wet, cold, and smelling of chlorine.
Some remarkable studies have been performed that confirm half of this peak-end rule. They involve giving 50% of a group of people (selected at random) an unpleasant experience, and the other half the same unpleasant experience with a shorter, somewhat less unpleasant experience tacked on the end of the primary experience. The latter group views the entire experience as having been less unpleasant than the former group does, and would be more willing to subject themselves to the experience again. This holds even though the latter group had more total moment to moment unpleasantness than the former group, and were subjected to unpleasantness for longer.
A similar issue to my swimming one can arise for experiences that we have never actually had before. When deciding whether we want them, we imagine what they are like, but this can be quite different from what they are in fact like. I have heard it said that this arises particularly often for sexual fantasies. People believe that they would really enjoy a particular experience (they do, in fact, enjoy imagining having that experience) but when they actually have it they find that it is unenjoyable in practice. And something akin to this is at risk of happening when people consider the question of whether they want to have children. If the visual image that the thought of having kids produces is one of sitting by a fireplace while beaming proudly at two well-behaved children with beaming smiles, then the feeling produced may well be “I want that!” But if the image is instead one of changing diapers, or trying to get your kids to stop screaming, or being woken up by a baby after two hours of sleep, the resulting feeling of wanting could be quite different.
Consider the problem that arises from these considerations. When we decide whether we want something, we often rely on our simulation or memory of that thing to make a decision. But our simulations and memories of experiences are not the same as the experiences themselves, and can be inaccurate representations. When we imagine something we run the risk of not understanding what that experience is really like. Therefore, when we say that we want something, we may only want it because of the particular aspects of it we happened to simulation, or because of inaccuracies in our simulation. However, if we force ourselves to think of many different aspects of the experience in question, rather than just one small part, that may lead to less arbitrary conclusions about what it is that we want. If your wanting depends heavily on the fact that (by chance, or due to a certain design feature of the human brain) you happened to imagine a particular part of the experience rather than another part of it, then the fact that you think you want it may not be very meaningful.
Nowadays, when I think about whether I want to swim, I try to get myself to imagine what the vast majority of the experience is like, not just the beginning and the end. I imagine actually swimming in the pool, which produces a positive mental state, rather than only thinking about jumping into the pool, which produces a negative one. As you’d expect, this produces a stronger feeling of wanting to swim than I had before.