In 1964 Phillip Converse wrote his ground breaking work, "The Nature of Belief Systems in Mass Publics", in which he challenged the idea that most people have structured, coherent opinions on which they base their political decisions. Forty years later this topic still seems to be fascinating to some and scary to others: a recent book, "The Myth of the Rational Voter", by Bryan Caplan attempts to shed new light on the issue, while Arnold Kling worries about "Two Strategies for avoiding Truth".

However, to what extent is it (or was it ever) reasonable to expect that the 'average citizen' really has a set of coherent opinions based on correct information? Doesn't the legitimacy of representative democracy rest on the idea that the average citizen can not decide on every issue, and for this reason she must choose others to make these decisions in her name?

The reality now and always is that individuals do not usually base their decision to support or reject a proposition on knowledge, but on values. Values play a central role in decision-making, particularly when it would really be very costly to be well informed about all the details of an issue (a necessary condition to make a rational or reasonable choice) or when difficult trade-off are involved.

This issue has been researched extensively in the area of public perception of science. For a long time we believed that, given enough information, most people would come to recognize that science has a positive impact on quality of life. However, research appears to indicate that a threshold exists beyond which values play a dominant role. For example, people who know embryos are destroyed in the process of extracting stem cells tend to be against stem cell research more than those who don't know. Furthermore, those who are against tend to view the embryo as a human rather than a cluster of cells and believe in larger numbers that life begins when the egg and sperm unite (both of these I treat as values, not knowledge). Nevertheless, irrespective of values, people who know more about science (measured through a 'quiz' type battery of questions) tend to support scientific research in general more than those who do less well on the quiz. More information and the survey results can be found on www.fbbva.es.

This 'knowledge paradox' has important consequences for politics and public policy, and raises some important ethical questions. Not only is it a question of to what extent should the public know 'the whole truth', but to what extent does the public want to know the whole truth? In our class discussion the other day about half the class agreed that the public has a right to know the truth, no matter what political games depend on it. We only timidly began to ask ourselves if people want to know, or if they prefer to trust their representatives to do what they think is right.

In an increasingly complex world, it doesn't seem reasonable to expect the 'average' person to make an informed decision on everything from stem cell research to the minimum wage to trade relations with China. The difficulty with this position lies in the failures of representative democracy: the less people know about everything, the easier it is for narrow-interest groups to highjack the political process and the greater the importance of having disciplined and professional political parties (and the greater the costs associated with politicians who dont do as promised during the campaign). Another difficulty, in the eyes of some people, is that values are much slower and harder to change than opinions. As future leaders in public policy, we need to consider these issues carefully in order to be more sensitive to our ultimate 'client', the public. Finally, yet another analysis leads us to identify with another class of under-represented citizens so large most of us don't notice them: the uninformed public, who is busy going to work and looking after the family, in the hope that their informed and like-minded representatives will decide with their interest in mind.

Next week, no more stem cells! Instead, I'll focus on education.