I do not do research on why people have a favourite coffee mug. I do research on fundamental mechanisms of learning and decision making, and how they are built into our brains. I was on the Today programme discussing the psychology of coffee last week and I mentioned favourite mugs (you can listen to what I said here, or read it in this Telegraph article which quotes me from that programme). I was asked to be on the Today programme because of an article I wrote in 2003, Psychology in the Coffee Shop. This was a light review and opinion piece about all the ways in which psychological theory intersects with the experience of drinking a cup of coffee. It is this article that comes up as the first hit if you google “psychology” and “coffee”.

This is my opinion, briefly, on favourite mugs: coffee and tea contain caffeine, which promotes dopamine release. Dopamine is a neurotransmitter, a chemical messenger in the brain, known to be intimately connected with learning and reward. The dopamine release brought about by a caffeinated drink hacks our natural learning mechanisms, causing them to seek to identify and repeat whatever is consistently associated with that dopamine release. This is why rituals, such as favourite coffee mugs, develop.

Before appearing on the Today programme I did ask myself if I should really be speaking to the media about something which is really no more than an entertaining opinion. I decided I should, partly because my research does cover the wider topics of learning and the development of preferences, partly because although it is just an opinion it is my professional, theory-motivated, opinion as a psychologist, and partly because I wanted my grandmother to be able to listen to me on radio 4.

I’ve been surprised by how much interest there is in the “why you have a favourite mug” aspect of what I’ve said. Several people have got in touch to ask about “my research into how coffee tastes out of favourite mugs”, or to find out how I “proved that coffee tastes better from your favourite mug”.
I have done no research into whether coffee does or does not taste better in your favourite mug. I am taking this as an accepted fact, for which I have offered a theoretical explanation. I regard the taste of the coffee from a favourite mug as something people can verify for themselves, without needing a psychologist to tell them. We all know that the drink is chemically the same from whatever mug it is served in, but yet people develop preferences. This is because taste and enjoyment are not merely about objective measurements, such as temperature, chemical composition and whatnot, but about psychological factors as well, such as the history of learning experiences that each individual has had.

Arguably, it might be something of a waste of public money if I spent my professional life asking people about their favourite coffee mugs. It is not clear that things such as this are interesting in themselves, or that anyone needs to have their choice of beverage receptacle validated by the latest research in psychological science. Despite the impression formed by some in the media, this is not what psychologists do. We investigate the fundamental principles of the operation of the mind, how they are played out in behaviour and how they are based in the brain. Sometimes we even make some progress in our understanding, and then are in the position to give a deeper perspective on some phenomenon with which everyone is familiar. This, I hope, is the case with the favourite coffee mug example.