Jens Koed Madsen

London School of Economics and Political Science | LSE

Protesters in leaderless movements face serious challenges when searching for reliable and trustworthy information in risky environments. Without formal structures to validate information, protestors are left to their own to evaluate the trustworthiness of information in a context where fake social media accounts and deception is possible. We inter...

Political issue polarisation worries scholars and the public alike. To understand what drives political issue polarisation, cross-national comparative research is necessary. Yet, measures of political issue polarisation which can be meaningfully applied across different countries are lacking. We propose a new technique for measuring political issue...

Inoculation theory research offers a promising psychological ‘vaccination’ against misinformation. But are people willing to take it? Expanding on the inoculation metaphor, we introduce the concept of ‘inoculation hesitancy’ as a framework for exploring reluctance to engage with misinformation interventions. Study 1 investigated whether individuals...

The didactic class is a pedagogical tool meant to increase classroom interactivity by encouraging student discussion of real-life cases in connection with theory. This paper evaluates the pedagogical impact of using a one-off didactic class where an external expert is brought in to discuss how to relate a cognitive psychology course’s content to re...

Many of the world’s fisheries are “data-limited” where the information does not allow precise determination of fish stock status and limits the development of appropriate management responses. Two approaches are proposed for use in data-limited stock management strategy evaluations to guide the evaluations and to understand the sources of uncertain...

In this paper, we outline a new proposal for communicating scientific debate to policymakers and other stakeholders in circumstances where there is substantial disagreement within the scientific literature. In those circumstances, it seems important to provide policy makers both with a useful, balanced summary that is representative of opinion in t...

It is important to incorporate fisher motivations and behavior into fisheries management models. Incorrect behavioral assumptions may yield ineffective incentives or interventions or even produce unintended consequences. To understand fisher behavior in a developing country, we surveyed 93 Indonesian snapper fishers. Results suggest they consider c...

The unchecked spread of misinformation is recognised as an increasing threat to public, scientific, and democratic health. Online networks are a contributing cause of this spread, with echo chambers and polarization indicative of the interplay between the selective search behaviours of users, and the reinforcement processes within the system those...

The use of data to inform and run political campaigning has become an inescapable trend in recent years. In attempting to persuade an electorate, micro-targeted campaigns (MTCs) have been employed to great effect through the use of tailored messaging and selective targeting. Here we investigate the capacity of MTCs to deal with the diversity of pol...

Misinformation has become an increasingly topical field of research. Studies on the 'Continued Influence Effect' (CIE) show that misinformation continues to influence reasoning despite subsequent retraction. Current explanatory theories of the CIE tacitly assume continued reliance on misinformation is the consequence of a biased process. In the pre...

Purpose - This viewpoint article is concerned with an attempt to advance Organisational Plasticity (OP) modelling concepts by using a novel community modelling framework (PhiloLab) from the Social Simulation community to drive the process of idea generation. In addition, we want to feed back our experience with PhiloLab, as we believe that this way...

Misinformation has become an increasingly topical field of research. Studies on the ‘Continued Influence Effect’ (CIE) show that misinformation continues to influence reasoning despite subsequent retraction. Current explanatory theories of the CIE tacitly assume continued reliance on misinformation is the consequence of a biased process. In the pre...

African elephants (Loxodonta africana) have undergone serious declines in the past century due to poaching for their ivory. Wildlife managers face significant challenges when planning poaching mitigation strategies, bounded by financial and logistical constraints. Quantitative models can provide practical insights for management, and many ‘equation...

Previous research concerning the effectiveness of public health campaigns have explored the impact of message design, message content, communication channel choice and other aspects of such campaigns. Meta analyses reported in the literature reveal, however, that the choice of endorsers in health campaigns remains unexplored. The present study addr...

Governing human-environmental ecosystems is a complex problem. Rule-based fisheries models are faced with several challenges. First, for large geographical problems like oceans, they require considerable time to find satisfactory solutions. Second, they tend to be reactive rather than anticipatory. Behavioural assumptions directly impact fishers’ c...

In this article, we explore how people revise their belief in a hypothesis and the reliability of sources in circumstances where those sources are either independent or are partially dependent because of their shared, common background. Specifically, we examine people's revision of perceived source reliability by comparison with a formal model of r...

Models of human dimensions of fisheries are important to understanding and predicting how fishing industries respond to changes in marine ecosystems and management institutions. Advances in computation have made it possible to construct agent‐based models (ABMs)—which explicitly describe the behaviour of individual people, firms or vessels in order...

Most bio-economic models in fisheries assume perfectly rational profit-maximizing behaviour by fishing vessels. Here we investigate this assumption empirically. Using a flexible agent-based model of fishing vessels called POSEIDON, we compared predicted fishing patterns to observed patterns in logbook data, that resulted from a wide range of styliz...

Social and cognitive psychological research and advances in behavioural economics have yielded a myriad of observations about people. This includes a desire to seek confirmatory evidence, a need for cognitive challenges, and personality traits. These can be measured so that campaigns may know which portion of the electorate is more or less risk ave...

In classic micro-targeted campaigns, data is used to segment people along lines such as beliefs, psychometrics, and relevance, which can be used to design persuasive efforts that optimally persuade each segment of voters. However, citizens are not passive consumers of information; they share their opinions with each other at work, in pubs, and via...

Our beliefs about the world are integral to how we can act within it. It may be tempting to assume that voters will support the candidate they believe is the best (or least bad) person for the job. Yet, beliefs do not deterministically yield corresponding behaviours. Competing preferences, inability, or force of habit may lead to behaviours that ar...

While we gain some information about the world through first-hand experiences, most of our information about the world comes from some source. We hear news from our friends, we learn about the world from news anchors and journalists, and we get daily weather reports from meteorologists. However, some sources cannot be trusted. People may lie, disto...

Ideally, political discourse is a lofty, earnest, and progressive discussion of competing ideologies, disagreement over the interpretation of available data and facts, and diverging predictions. In real life, however, politics can be poor, nasty, brutish, and short. Negative attack adverts that slander or denigrate opposing ideologies or persons em...

Classical models predominantly approach persuasion qualitatively or descriptively. In the past couple of decades, researchers have explored quantitative and predictive models to describe how people integrate new evidence within their pre-existing beliefs. The so-called Bayesian models take point of departure in people’s subjective view of the world...

While the micro-targeted approaches are never deterministic or all-powerful, they give the user a distinct strategic advantage if they are carried out well. As campaigns become increasingly costly to conduct, politicians enter an arms race for campaign finances, which may skew political attention and introduce undesirable elements into the body pol...

The ability to change the beliefs of others is a foundational principle of deliberative democracies. People who can sway the hearts and minds of the electorate gain significant social advantages. Unsurprisingly, people have explored how persuasion works since Ancient Athenian democracies. This chapter explores the history of persuasion from qualita...

Analytic models segment the electorate into distinct categories. Comparatively, dynamic models allow for interaction between system components, as they unfold over time. As systems become increasingly complex, analytic models are increasingly unable to track the consequences of intervening into the system. Given the fact that elections are highly c...

In order to run election campaigns effectively, campaign managers have to appreciate how the democratic system in question functions. Different deliberative democracies are governed by specific rules that impact optimal campaign strategies and voter relevance. If a democracy is proportional, all voters are equally relevant, and each voter is as imp...

Personalised data can tell campaigns about people’s political convictions and preferences, their personal beliefs, and their perception of candidate credibility. In addition, data can be used to estimate psychometric traits that campaign managers believe are salient for the electorate such as biases, dispositions, or personality traits. Finally, an...

Sequential testimonies where more or less reliable sources argue about an issue are central to public debates. Often, the majority of sources may argue that a hypothesis is true while a minority dissenter may claim the opposite (e.g. scientists and lobbyists in the climate change debate). In this paper, we show that people are sensitive to source r...

Misinformation, and its impact on society, has become an increasingly topical field of study of late. A body of literature exists that suggests misinformation can retain an influence over beliefs despite subsequent retraction, known as the Continued Influence Effect (CIE). Researchers have argued this to be irrational. However, we show using a Baye...

Some well-established scientific findings may be rejected by vocal minorities because the evidence is in conflict with political views or economic interests. For example, the tobacco industry denied the medical consensus on the harms of smoking for decades, and the clear evidence about human-caused climate change is currently being rejected by many...

Computational cognitive models typically focus on individual behavior in isolation. Models frequently employ closed-form solutions in which a state of the system can be computed if all parameters and functions are known. However, closed-form models are challenged when used to predict behaviors for dynamic, adaptive, and heterogeneous agents. Such s...

Sustainable management of complex human–environment systems, and the essential services they provide, remains a major challenge, felt from local to global scales. These systems are typically highly dynamic and hard to predict, particularly in the context of rapid environmental change, where novel sets of conditions drive coupled socio-economic-envi...

This book examines the psychology behind micro-targeted tactics used in election campaigning and the advent of increasingly sophisticated dynamic Agent-Based Models (ABMs). It discusses individual profiling, how data and modelling are deployed to enhance the effectiveness of persuasion and mobilization efforts in campaigns, and the potential limita...

Models of human dimensions of fisheries are important to understanding and predicting how fishing industries respond to changes in marine ecosystems and management institutions. Advances in computation have made it possible to construct agent-based models (ABMs)—which explicitly describe the behaviour of individual people, firms, or vessels in orde...

Echo chambers (ECs) are enclosed epistemic circles where like-minded people communicate and reinforce pre-existing beliefs. It remains unclear if cognitive errors are necessarily required for ECs to emerge, and then how ECs are able to persist in networks with available contrary information. We show that ECs can theoretically emerge amongst error-f...

The article examines whether female political candidates are disfavored in terms of persuasiveness potential based on their expertise and trustworthiness. Using a Bayesian argumentation paradigm in which candidates endorse policies, this study shows that male voters regard female candidates as less persuasive than male candidates. A controlled betw...

Most geographical agent-based models simulate agents through custom-made decision-making algorithms. This makes it difficult to assess which results are general and which are contingent on the algorithm's details. We present a set of general algorithms, applicable in any agent-based model for choosing repeatedly from a set of alternatives. We showc...

By recasting indirect inference estimation as a prediction rather than a minimization and by using regularized regressions, we can bypass the three major problems of estimation: selecting the summary statistics, defining the distance function and minimizing it numerically. By substituting regression with classification we can extend this approach t...

In political campaigns, perceived candidate credibility influences the persuasiveness of messages. In campaigns aiming to influence people’s beliefs, micro-targeted campaigns (MTCs) that target specific voters using their psychological profile have become increasingly prevalent. It remains open how effective MTCs are, notably in comparison to popul...

Predicting the effect of persuasion campaigns is difficult, as belief changes may cascade through a network. In recent years, political campaigns have adopted micro-targeting strategies that segment voters into fine-grained clusters and target those cluster more specifically. At present, there is little evidence that explores the efficiency of this...

Conspiracy theories cover topics from politicians to world events. Frequently, proponents of conspiracies hold these beliefs strongly despite available evidence that may challenge or disprove them. Therefore, conspiratorial reasoning has often been described as illegitimate or flawed. Here, we explore the possibility of growing a rational (Bayesian...

Most models of cognitive function focus on internal structures while neglecting interactive and multi-scalar temporal elements. The current chapter advances the argument that cognition cannot be defined in isolation of three components: internal mechanisms (e.g. neural connections as well as our bodies), externally distributed interactions (e.g. sa...

The appeal to expert opinion is an argument form that uses the verdict of an expert to support a position or hypothesis. A previous scheme-based treatment of the argument form is formalized within a Bayesian network that is able to capture the critical aspects of the argument form, including the central considerations of the expert's expertise and...

Various disciplines such as rhetoric, marketing, and psychology have explored persuasion as a social and argumentative phenomenon. The present thesis is predominantly based in cognitive psychology and investigates the psychological processes the persuadee undergoes when faced with a persuasive attempt. The exploration concludes with the development...

Book synopsis: Since Aristotle, the study of rhetoric has focused on the persuasive aspect of verbal discourse in the political, forensic and ceremonial domains. Rhetoric deals with doxa, with public discourse and persuasion as they develop in a world with no absolute knowledge, certainty or fixity. Changing cultural and political conditions urge u...

En undersøgelse blandt rådgivende ingeniører, Børsens Ledelseshåndbøger I (December) The following presents the results of a survey study in 2012 was conducted among the 352 Danish consulting engineering companies that have between 2 and 199 employees. The study focused on their participation in multi-partner projects, defined as projects where at...

Bayesian probability has recently been proposed as a normative theory of argumentation. In this article, we provide a Bayesian formalisation of the ad Hitlerum argument, as a special case of the ad hominem argument. Across three experiments, we demonstrate that people's evaluation of the argument is sensitive to probabilistic factors deemed relevan...

The article focuses on the definition of persuasion and how it relates to rhetorical theory. The investigation covers four brief literature reviews on rhetoric, psychology, marketing and economics in order to determine what is essentially and necessarily persuasive and what is frequently conjoined. The general finding is that rhetorical theory is t...