Abstract

Judging the state of a bridge based on SHM observations is an inference process, which should be rationally carried out using a logical approach. However, it is often observed that real-life decision makers depart from this ideal model of rationality, judge and decide using common sense, and privilege fast and frugal heuristics to rational analytic thinking. For instance, confusion between condition state and safety of a bridge is one of the most frequently observed examples in bridge management. The aim of this paper is to describe mathematically this observed biased judgement, a condition that is broadly described by Kahneman and Tversky’s representativeness heuristic. Particularly, the paper examines how this heuristic affects the interpretation of data, providing a deeper understanding of the differences between a method affected by cognitive biases and the classical rational approach. Based on the literature review, three different models reproducing an individual behaviour distorted by representativeness are identified. These models are applied to the case of a transportation manager who wrongly judges a particular bridge unsafe simply because deteriorated, regardless its actual residual load-carrying capacity. It is demonstrated that the application of any of the three heuristic judgment models correctly predicts that the manager will mistakenly judge the bridge as unsafe based on the observed condition state. It is not objective of the paper to suggest that representativeness should be used instead of rational logic, however, understanding how real-life managers actually behave is of paramount importance when setting a general policy for bridge maintenance.

摘要

根据 SHM 观察判断桥梁的状态是一个推理过程，应使用逻辑方法合理地进行。然而，经常观察到现实生活中的决策者背离了这种理想的理性模型，使用常识进行判断和决定，并将快速和节俭的启发式方法优先于理性分析思维。例如，桥梁的状况状态和安全性之间的混淆是桥梁管理中最常见的例子之一。本文的目的是从数学上描述这种观察到的有偏见的判断，卡尼曼和特沃斯基的代表性启发式广泛描述了这种情况。特别是，本文研究了这种启发式方法如何影响数据的解释，提供对受认知偏差影响的方法与经典理性方法之间差异的更深入理解。根据文献综述，确定了三种不同的模型，它们再现了被代表性扭曲的个人行为。这些模型应用于运输经理的案例，他错误地判断某座特定桥梁不安全，只是因为它已经损坏，而不管其实际剩余承载能力。证明了三个启发式判断模型中的任何一个的应用都正确地预测了管理者将根据观察到的条件状态错误地判断桥梁是不安全的。本文的目的不是建议应该使用代表性而不是理性逻辑，但是，