How Much Rationality Is Needed for Decision Making?

The Braess paradox (discovered in 1968 by the German mathematician Dietrich Braess) describes how a possible relief of a system, by introducing new possibilities to distribute load or local density in flows inside the system, can actually increase stress on the system. It is most often researched in a world of rational decision-makers, who are assumed to cause the worsening situation due to rational optimization of individual interests. In strongly complex networks, the exploitation of new possibilities most probably needs rational decision-makers who can see the use of new possibilities for them. Interestingly, a mechanical analogy of the situation also exists, where new possibilities—in this case for forces in a system to attack—lead to a loss of stability inside the system. In this example, a string that was introduced to relieve the load on two springs leads to counter-intuitive overloading. With the perspective that the evolution of information processing systems is already beginning in a physical and chemical pre-biotic world, this is an interesting case that might give further insight into how and when choices between many possibilities could threaten the function of a system rather than making it more durable and adaptable. The example is discussed based on a review of literature from the humanities as well as the natural sciences.