Interesting bit on S&M about choice here. There are a couple of other things I would add . First, people often don’t really choose – as in make an active decision – when offered a choice. It’s too much mental effort, and we don’t have much energy to spare it seems. According this book (only about a third of which is any good) the energy-efficient nature of our brains encourages us to take mental short cuts. This partly explains things like why we fall for optical illusions.
In terms of consumer choices often we seem to simply do what we’ve always done because it's easy, a point made in this. If we use choices made to infer decisions made then this can appear to be a strong preference when actually it’s almost the opposite – a lack of effort. A regular choice does not necessarily mean we are knocked out by our purchase, as my own sandwich-buying activity reveals.
Secondly, we also seem to misread our own past decisions. In Dan Ariely’s latest book he details how decisions made in an emotional state are (wrongly) judged by our later – more coolly rational selves – to have been based on sound reasoning. And we use that past decision to inform future ones, so we are almost subject to our own personal information cascade.
Having said all that, having the option of choice does seem to be important to us, even if we rarely actively exercise it, presumably because it links to our sense of self-determination.