If attitudes were measured easily and uniformly for the first sixty years of their existence, in the 1990s there was something of a revolution in the measurement of attitudes and indeed in our whole approach to the topic. What drove this revolution was what psychologists like to call the ‘attitudebehaviour problem’ – the fact that attitudes and behaviour often simply fail to match up, and that attitudes measured in this way often do not predict behaviour in quite the way that many had hoped.