Complex Dynamics of Human Migration: Beyond Linear Thinking

Somalia is one of the countries suffering from severe environmental and socio-political situations without well-operating state power. Such conditions lead to huge population movements within the country. While many researchers attempted to understand these movements, conventional approaches (e.g., econometric modeling, logistic regression) are restricted to fully capture the underlying mechanisms of migration. Alternatively, I use multiple analytical techniques from complex systems science, including network analysis and modeling, event coincidence analysis, and causality detection. First, systematic network patterns are observed throughout multiple years. Transitive movements, which involve both direct and indirect movements via transit to migrate from an origin to a destination, clearly exist in internal displacement networks regardless of the driver (e.g., conflict or drought). Second, migration timings follow either bursty or Poisson dynamics depending on the external forces. If a district is not highly affected by external forces, migration timings in the district are likely to follow bursty dynamics due to self-organization. In the opposite case, Poisson processes work better. Third, external stressors drive migration differently in dry and rainy seasons. While the effects of socio-political and environmental drivers vary, network effects exist regardless of the season. Lastly, cascading behaviors are found, making migration decisions to be collective behaviors. Thus, a shock may propagate and lead to migration decisions in a remote place. These are just a few examples of the complex and higher-ordered dynamics of human migration. To grasp the full picture of human migration, more works beyond linear thinking are required in the future.