Max Planck Institute for the Study of Crime, Security and Law, Freiburg im Breisgau, Germany.
Institute for Education and Child Studies, Faculty of Social and Behavioural Sciences, Leiden University, Leiden, The Netherlands.
Proc Biol Sci. 2023 Feb 22;290(1993):20222095. doi: 10.1098/rspb.2022.2095.
There is massive variation in rates of violence across time and space. These rates are positively associated with economic deprivation and inequality. They also tend to display a degree of local persistence, or 'enduring neighbourhood effects'. Here, we identify a single mechanism that can produce all three observations. We formalize it in a mathematical model, which specifies how individual-level processes generate the population-level patterns. Our model assumes that agents try to keep their level of resources above a 'desperation threshold', to reflect the intuitive notion that one of people's priorities is to always meet their basic needs. As shown in previous work, being below the threshold makes risky actions, such as property crime, beneficial. We simulate populations with heterogeneous levels of resources. When deprivation or inequality is high, there are more desperate individuals, hence a higher risk of exploitation. It then becomes advantageous to use violence, to send a 'toughness signal' to exploiters. For intermediate levels of poverty, the system is bistable and we observe : populations can be violent because they were deprived or unequal in the past, even after conditions improve. We discuss implications of our findings for policy and interventions aimed at reducing violence.
暴力的发生频率在时间和空间上存在巨大差异。这些比率与经济贫困和不平等呈正相关。它们也往往表现出一定程度的局部持续性，或“持久的邻里效应”。在这里，我们确定了一个单一的机制，可以产生所有这三种观察结果。我们将其形式化在一个数学模型中，该模型指定了个体层面的过程如何产生群体层面的模式。我们的模型假设，代理人试图将他们的资源水平保持在一个“绝望门槛”之上，以反映这样一种直观的概念，即人们的首要任务之一是始终满足他们的基本需求。如前所述工作，处于阈值以下会使冒险行为（如财产犯罪）受益。我们用具有不同资源水平的人群进行模拟。当贫困或不平等程度较高时，绝望的人就越多，因此被剥削的风险就越高。因此，使用暴力来向剥削者发出“强硬信号”是有利的。对于中等程度的贫困，该系统是双稳态的，我们观察到：即使条件改善后，过去因贫困或不平等而产生的暴力行为仍会存在于人群中。我们讨论了我们的发现对旨在减少暴力的政策和干预措施的影响。
