Migration systems, pioneers and the role of agency

The notion of a migration system is often invoked but it is rarely clearly defined or conceptualized. De Haas has recently provided a powerful critique of the current literature highlighting some important flaws that recur through it. In particular, migration systems tend to be identified as fully formed entities, and there is no theorization as to how they come into being. Moreover, there is no explanation of how they change in time, in particular how they come to decline. The inner workings – the mechanics – which drive such changes are not examined. Such critiques of migration systems relate to wider critiques of the concept of systems in the broader social science literature, where they are often presented as black boxes in which human agency is largely excluded. The challenge is how to theorize the mechanics by which the actions of people at one time contribute to the emergence of systemic linkages at a later time. This paper focuses on the genesis of migration systems and the notion of pioneer migration. It draws attention both to the role of particular individuals, the pioneers, and also the more general activity of pioneering which is undertaken by many migrants. By disentangling different aspects of agency, it is possible to develop hypotheses about how the emergence of migrations systems is related to the nature of the agency exercised by different pioneers or pioneering activities in different contexts.migration systems, agency, emergence, pioneer migrants, migrant networks, social capital

The status quo bias of bond market analysts

Status quo bias is a systematic cognitive error which makes it difficult for individuals to make decisions independently of the currently dominant situation. This study pursues the question of whether bond market analysts are affected by status quo bias. We evaluated interest rate forecast series from twelve industrial nations. This revealed that, on average, forecasts were much too close to the status quo - the current interest rate at the time when the forecast was made. With the aid of various analytical procedures it can be shown that the actual extent of interest rate changes is systematically and significantly underestimated

Network centrality and stock market volatility: The impact of communication topologies on prices

We investigate the impact of agent communication networks on prices in an artificial stock market. Networks with different centralization measures are tested for their effect on the volatility of prices. Trading strategies diffuse through the different network topologies, mimetic contagion arises through the adaptive behavior of the heterogeneous agents. Short trends may trigger cascades of buy and sell orders due to increased diffusion speed within highly centralized communication networks. Simulation results suggest a correlation between the network centralization measures and the volatility of the resulting stock prices

Informational Cascades: A Mirage?

Experimental research found contradictory results regarding the occurrence of informational cascades. Whereas Anderson and Holt (1997) confirmed the model of Banerjee (1992), and Bikhchandani et al. (1992) through lab tests, Huck and Oechssler (2000) came to contradictory results on crucial issues. This article presents experimental evidence supporting further doubts concerning "Bayesian" informational cascades: Just under two thirds of all decisions are characterized by an excessive orientation towards the private signal, and only a small number of the subjects (<6%) make rational decisions systematically and consistently

Topology for gaze analyses - Raw data segmentation

Recent years have witnessed a remarkable growth in the way mathematics, informatics, and computer science can process data. In disciplines such as machine learning, pattern recognition, computer vision, computational neurology, molecular biology, information retrieval, etc., many new methods have been developed to cope with the ever increasing amount and complexity of the data. These new methods offer interesting possibilities for processing, classifying and interpreting eye-tracking data. The present paper exemplifies the application of topological arguments to improve the evaluation of eye-tracking data. The task of classifying raw eye-tracking data into saccades and fixations, with a single, simple as well as intuitive argument, described as coherence of spacetime, is discussed, and the hierarchical ordering of the fixations into dwells is shown. The method, namely identification by topological characteristics (ITop), is parameter-free and needs no pre-processing and post-processing of the raw data. The general and robust topological argument is easy to expand into complexsettings of higher visual tasks, making it possible to identify visual strategies. As supplementary file an interactive demonstration of the method can be downloaded

Rationales Herdenverhalten bei US-amerikanischen Rentenmarkt-Analysten: Verhaltensabstimmung durch ein externes Signal

"Experimental research found contradictory results regarding the occurrence of informational cascades. Whereas Anderson and Holt (1997) confirmed the model of Banerjee (1992), and Bikhchandani, Hirshleifer, and Welch (1992) through lab tests, Huck and Oechssler 2000) came to controversial results for crucial issues. This study is an extensive (227 test persons) - and as regards contents - expanded repetition. In conclusion, less than 10% of subjects are able to make deductions about predecessors’ private signals from their actions, to consider the reliability of the signals and the a priori probability, to accurately use Bayes’ Rule, and to thus reach rational decisions." (author's abstract