What is the role of social interactions in the creation of price bubbles? Answering this question requires obtaining collective behavioural traces generated by the activity of a large number of actors. Digital currencies offer a unique possibility to measure socio-economic signals from such...

We develop a agent-based framework to model the emergence of collective emotions, which is applied to online communities. Agents individual emotions are described by their valence and arousal. Using the concept of Brownian agents, these variables change according to a stochastic dynamics, which...

Excessive leverage, i.e. the abuse of debt financing, is considered one of the primary factors in the default of financial institutions. Systemic risk results from correlations between individual default probabilities that cannot be considered independent. Based on the structural framework by...

How do humans respond to indirect social influence when making decisions? We analysed an experiment where subjects had to repeatedly guess the correct answer to factual questions, while having only aggregated information about the answers of others. While the response of humans to aggregated...

Power grids, road maps, and river streams are examples of infrastructural networks which are highly vulnerable to external perturbations. An abrupt local change of load (voltage, traffic density, or water level) might propagate in a cascading way and affect a significant fraction of the network....

We introduce uncertainty in our general equilibrium model with multi-member groups, following the classical state-space approach of Arrow- Debreu. A host of new interesting economic issues emerge. First, risk averse agents can attempt to insure themselves through markets or through mutual...

\begin{abstract} We analyse time series of CDS spreads for a set of major US and European institutions on a period overlapping the recent financial crisis. We extend the existing methodology of \emph{$\varepsilon$-drawdowns} to the one of \emph{joint $\varepsilon$-drawups}, in order to estimate...

We investigate whether the set of Kreps and Porteus (1978) preferences include classes of preferences that are stationary, monotonic and well-ordered in terms of risk aversion. We prove that the class of preferences introduced by Hansen and Sargent (1995) in their robustness analysis is the only...

With our knowledge of the universe, we have sent men to the moon. We know microscopic details of objects around us and within us. And yet we know relatively little about how our society works and how it reacts to changes brought upon it. Humankind is now facing serious crises for which we must...

We introduce a general framework for models of cascade and contagion processes on networks, to identify their commonalities and differences. In particular, models of social and financial cascades, as well as the fiber bundle model, the voter model, and models of epidemic spreading are recovered...