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Simone RIGHI

Professore Associato
Dipartimento di Economia "Marco Biagi"

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Pubblicazioni

2024 - The Clientele Effects in Equity Crowdfunding: a Complex Network Analysis [Articolo su rivista]
Righi, Riccardo; Pedrazzoli, Alessia; Righi, Simone; Venturelli, Valeria
abstract

The study develops an original interdisciplinary approach, leveraging complex networks through which it identifies groups of investors and projects in equity crowdfunding, investigates whether clientele effects arise resulting in specific investor-entrepreneur matching, and explores which investor-entrepreneur combinations can lead to the emergence of collective behaviors. Data about campaigns and investors are gathered from Crowdcube to identify investors and company types that populated this leading UK platform during its early years (2011–2016). Results show that the clientele effect exists only between specific investors and project types: serial investors are attracted to innovative companies, whereas high-value and small investors, representing the largest group in the crowd, prefer mature companies in the consumer product industry. Moreover, the study reveals that information exchange in certain matching drives the clientele effect, resulting in collective behavior on specific segments: small investors engage in collective behaviors only when targeting high-tech innovative companies. These findings provide a new view on the clientele effect in equity crowdfunding platforms and the financing of innovative companies.

2024 - Understanding post disaster prosociality: Comparing post earthquake cooperation and fairness in two Italian regions [Articolo su rivista]
Pancotto, Francesca; Giardini, Francesca; Righi, Simone
abstract

Natural disasters put an enormous strain on communities' ability to cooperate. Community resilience, which heavily depends on individuals’ prosocial attitudes, reduces the effects of disasters, determining completely different dynamics even in neighboring regions. We designed an exploratory empirical study in which we collected empirical data on behavior in two games together with survey data in seven municipalities located in two Italian regions affected by two major earthquakes. We measured contributions in the Public Goods Game and fairness in a modified Dictator Game, with the aim of testing for the effects of damage suffered, and embeddedness in the community on prosociality. We compared two different explanations, damage suffered and embeddedness, and we concluded that, in our sample, embeddedness was not related to differences in contributions, while damage suffered by the individuals was. This study contributes to the literature on post-disaster prosociality by presenting a unique lab–in-the-field experiment, and showing the differential impact of the same disaster in neighboring regions.

2023 - Complexity of Behavioural Strategies and Cooperation in the Optional Public Goods Game [Articolo su rivista]
Podder, S.; Righi, S.
abstract

The problem of collective action where—beside the standard options of cooperating and defecting—there is also the possibility of opting out has been extensively studied through the optional public good game (OPGG). Within this and other social dilemma games, reputation systems, composed of a social norm—assigning reputations to agents—and a set of behavioural strategies using this information to condition their behaviour, are able to sustain cooperation. However, while the relationship between the complexity of social norms and cooperation has been extensively studied, the same cannot be said with respect to behavioural strategies, due to high dimensionality of the strategy spaces involved. We deal with this problem by building an agent-based model where agents adopt simple social norms, play the OPGG and learn behavioural strategies through a genetic algorithm. We show that while social norms which assign different reputations to defectors and to agents opting out achieve the highest levels of cooperation, the social norms that do not distinguish between these actions do improve cooperation levels with respect to the baseline when behavioural strategies are sufficiently complex. Furthermore, we find that cooperation increases when the interaction groups are small enough for agents to accurately distinguish between different behaviours.

2023 - Food waste between environmental education, peers, and family influence. Insights from primary school students in Northern Italy [Articolo su rivista]
Piras, S.; Righi, S.; Banchelli, F.; Giordano, C.; Setti, M.
abstract

Education plays a central role in tackling consumers' food waste. However, research on children's food waste at school tends to focus on quantification and logistical factors rather than on the impact of interventions. Furthermore, behavioural elements, including imitation, tend to be neglected despite their well-established role in the food realm. To contribute to filling this gap, we assess the short and long-term impact on food waste levels of a lesson about the environmental consequences of food waste. Innovating on the literature, we control for both behavioural factors and social influence. For this purpose, we developed a longitudinal protocol that factors in altruistic concerns elicited through economic experiments, and the influence of parents and classmates assessed through parents' questionnaires and network questions. We apply the protocol to a sample of 420 Italian primary school students from 20 classes. The lesson was implemented in half of the classes, randomly selected. We find that the lesson only reduces self-declared food waste in the short-term but the impact does not persist after some months. Concerns for the environmental implications of food waste increase significantly, and this effect is still present in the longer-term. Neither the parents' approach to wasting food nor the degree of students' pro-social motivations make a significant difference. In turn, students' food waste is found to align with that of the students sitting nearby in the school canteen, suggesting that imitation through direct observation of behaviours plays an important role. These results call policymakers to take advantage of network effects in social settings to favour the replication of pro-environmental behaviours.

2023 - Regionalisation and cross-region integration. Twin dynamics in the automotive international trade networks [Articolo su rivista]
Russo, Margherita; Alboni, Fabrizio; Sanginés, Jorge Carreto; De Domenico, Manlio; Mangioni, Giuseppe; Righi, Simone; Simonazzi, Annamaria
abstract

The paper analyses the changes that occurred over 25 years in the geography of trade in automotive parts and components. Using the Infomap multilayer clustering algorithm, we identify clusters of countries and their specific trades in the automotive international trade network, we measure the relative importance of each cluster and the interconnections between them, and we analyse the contribution of countries and of trade of components and parts in the clusters. The analysis highlights the formation of denser and more hierarchical networks generated by Germany's trade relations with EU countries and by the US preferential trade agreements with Canada and Mexico, as well as the surge of China. While the relative importance of the main clusters and of some individual countries change significantly, connections between clusters increase over time.

2023 - Voluntary play increases cooperation in the presence of punishment: a lab in the field experiment [Articolo su rivista]
Pancotto, F.; Righi, S.; Takacs, K.
abstract

Problems of cooperation have often been simplified as the choice between defection and cooperation, although in many empirical situations it is also possible to walk away from the interaction. We present the results of two lab-in-the-field experiments with a diverse pool of subjects who play optional and compulsory public goods games both with and without punishment. We find that the most important institution to foster cooperation is punishment, which is more effective in a compulsory game. In contrast to Rand and Nowak (Nat Commun 2(1):1–7, 2011), we find that loners are not responsible for anti-social punishment, which is mostly imputable to low-contributors (free-riders). Loners neither totally free-ride nor they significantly punish cooperators (or other types of players): they simply avoid all forms of participation whenever possible.

2022 - From social interactions to private environmental behaviours: The case of consumer food waste [Articolo su rivista]
Piras, Simone; Righi, Simone; Setti, Marco; Koseoglu, Nazli; Grainger, Matthew J.; Stewart, Gavin B.; Vittuari, Matteo
abstract

Consumer food waste, like many environmental behaviours, takes place in private, and is not directly subject to social monitoring. Nevertheless, social interactions can affect private opinions and behaviours. This paper builds an agent-based model of interactions between consumers heterogeneous in their sociability, their initial opinions and behaviours related to food waste, and their willingness to consider different opinions, in order to assess how social interactions can affect private behaviours. Compared to existing models of opinion dynamics, we innovate by including a range of “cognitive dissonance” between stated opinions and actual behaviours that consumers are willing to accept before changing one of the two. We calibrate the model using questionnaire data on household food waste in Italy. We find that a limited degree of mixing between different socio-demographic groups, namely adult and young consumers, is enough to trigger change, but a certain openness of mind is required from more wasteful individuals. Equally, a small group of environmentally committed consumers can attract a sizeable share of the population towards low-waste behaviours if they show a certain variability of opinions and are willing to compromise with individuals in their close neighbourhood in terms of opinions. These findings can help design effective interventions to promote pro-environmental behaviours, taking advantage of the beneficial network effects while anticipating negative externalities.

2022 - Gossip: Perspective Taking to Establish Cooperation [Articolo su rivista]
Righi, Simone; Takács, Károly
abstract

Problems of cooperation are frequent among living organisms, but they are difficult to solve. Humans have been able to produce large-scale cooperation among unrelated individuals through reputation systems. A challenging puzzle, however, is how reputation can guide behavior if in most cases it is not shared publicly and is assigned to others privately. We confirm that it is difficult to obtain cooperation among agents playing the Prisoner’s Dilemma when reputations are individually assigned. We propose that third-party communication (gossip) can overcome this difficulty, but only under specific conditions concerning its content, amount and persistence. We show that—in order to sustain cooperation—gossip should not only be about private evaluations of others but should also include perspective taking and exchange of information about tolerance thresholds to support cooperation. This perspective taking reputational strategy can propagate and establish cooperation in the population independent of gossip frequency and population size, under various selection mechanisms of communication partners and targets, and assumptions concerning agents’ memory.

2021 - Community social capital and status: The social dilemma of food waste [Articolo su rivista]
Piras, Simone; Pancotto, Francesca; Righi, Simone; Vittuari, Matteo; Setti, Marco
abstract

In developed countries, the largest share of food is wasted at the household level. Household food waste results from a complex interaction between economic factors, well-established routines, and social norms. To explain this interaction, we propose a simple model of waste behavior where the individual and social economic costs generated by wasting are counterbalanced by the security and status generated through acquiring excess food, thus causing a social dilemma. This trade-off is mediated by social capital, which measures the intensity with which each individual within a community evaluates the negative effects of waste. We test this model's hypotheses using a 2016 dataset of food behaviors and opinions of Italian households, which we merge with variables known to elicit the local level of social capital. We find individual food waste levels to be negatively related with social capital. Contrastingly, status concerns with respect to food and the lack of organizational abilities are both more prevalent in low social capital areas, and are related to increased food waste. This relationship is mediated by income.

2021 - Local reputation, local selection, and the leading eight norms [Articolo su rivista]
Podder, Shirsendu; Righi, Simone; Takács, Károly
abstract

Humans are capable of solving cooperation problems following social norms. Social norms dictate appropriate behaviour and judgement on others in response to their previous actions and reputation. Recently, the so-called leading eight norms have been identified from many potential social norms that can sustain cooperation through a reputation-based indirect reciprocity mechanism. Despite indirect reciprocity being claimed to extend direct reciprocity in larger populations where direct experiences cannot be accumulated, the success of social norms have been analysed in models with global information and evolution. This study is the first to analyse the leading eight norms with local information and evolution. We find that the leading eight are robust against selfish players within most scenarios and can maintain a high level of cooperation also with local information and evolution. In fact, local evolution sustains cooperation under a wider set of conditions than global evolution, while local reputation does not hinder cooperation compared to global reputation. Four of the leading eight norms that do not reward justified defection offer better chances for cooperation with quick evolution, reputation with noise, larger networks, and when unconditional defectors enter the population.

2021 - Multidimensional Clustering of EU Regions: A Contribution to Orient Public Policies in Reducing Regional Disparities [Articolo su rivista]
Pavone, Pasquale; Pagliacci, Francesco; Russo, Margherita; Righi, Simone; Giorgi, Anna
abstract

This paper applies multidimensional clustering of EU-28 regions with regard to their specialisation strategies and socioeconomic characteristics. It builds on an original dataset. Several academic studies discuss the relevant issues to be addressed by innovation and regional development policies, but so far no systematic analysis has linked the different aspects of EU regions research and innovation strategies (RIS3) and their socio-economic characteristics. This paper intends to fill this gap, with the aim to provide clues for more effective regional and innovation policies. In the data set analysed in this paper, the socioeconomic and demographic classification associates each region to one categorical variable (with 19 categories), while the classification of the RIS3 priorities clustering was performed separately on “descriptions” (21 Boolean categories) and “codes” (11 Boolean Categories) of regions’ RIS3. The cluster analysis, implemented on the results of the correspondence analysis on the three sets of categories, returns 9 groups of regions that are similar in terms of priorities and socioeconomic characteristics. Each group has different characteristics that revolve mainly around the concepts of selectivity (group’s ability to represent a category) and homogeneity (similarity in the group with respect to one category) with respect to the different classifications on which the analysis is based. Policy implications showed in this paper are discussed as a contribution to the current debate on post-2020 European Cohesion Policy, which aims at orienting public policies toward the reduction of regional disparities and to the enhance complementarities and synergies within macro-regions.

2021 - Reflectivity relates differently to pro sociality in naïve and strategic subjects [Articolo su rivista]
Pancotto, F.; Righi, S.
abstract

Is pro sociality a natural impulse or the result of a self-controlled behavior? We investigate this issue in a lab in the field experiment with participants from the general adult population in Italy. We find two key results: first, that there is a positive relationship between pro sociality and strategic reasoning. Second, that reflectivity relates to lower pro sociality but only among strategic subjects, indicating that the intuitive view of pro sociality is valid only among strategic individuals. Non-strategic individuals are instead intuitively selfish. We surmise that these results emerge due to a common cognitive root between strategizing and pro sociality, namely empathy.

2021 - Reputation and punishment sustain cooperation in the optional public goods game [Articolo su rivista]
Podder, S.; Righi, S.; Pancotto, F.
abstract

Cooperative behaviour has been extensively studied as a choice between cooperation and defection. However, the possibility to not participate is also frequently available. This type of problem can be studied through the optional public goods game. The introduction of the 'Loner' strategy' allows players to withdraw from the game, which leads to a cooperator-defector-loner cycle. While pro-social punishment can help increase cooperation, anti-social punishment - where defectors punish cooperators - causes its downfall in both experimental and theoretical studies. In this paper, we introduce social norms that allow agents to condition their behaviour to the reputation of their peers. We benchmark this with respect both to the standard optional public goods game and to the variant where all types of punishment are allowed. We find that a social norm imposing a more moderate reputational penalty for opting out than for defecting increases cooperation. When, besides reputation, punishment is also possible, the two mechanisms work synergically under all social norms that do not assign to loners a strictly worse reputation than to defectors. Under this latter set-up, the high levels of cooperation are sustained by conditional strategies, which largely reduce the use of pro-social punishment and almost completely eliminate anti-social punishment. This article is part of the theme issue 'The language of cooperation: reputation and honest signalling'.

2020 - Bring a friend! Privately or Publicly? [Articolo su rivista]
Carroni, Elias; Pin, Paolo; Righi, Simone
abstract

We study the optimal referral strategy of a seller and its relationship with the type of communication channels among consumers. The seller faces a partially uninformed population of consumers, interconnected through a directed social network. In the network, the seller offers rewards to informed consumers (influencers) conditional on inducing purchases by uninformed consumers (influenced). Rewards are needed to bear a communication cost and to induce word of mouth (WOM) either privately (cost per contact) or publicly (fixed cost to inform all friends). From the seller’s viewpoint, eliciting Private WOM is more costly than eliciting Public WOM. We investigate (1) the incentives for the seller to move to a denser network, inducing either Private or Public WOM, and (2) the optimal mix between the two types of communication. A denser network is found to be always better not only for information diffusion but also for seller’s profits, as long as Private WOM is concerned. Differently, under Public WOM, the seller may prefer an environment with less competition between informed consumers, and the presence of highly connected influencers (hubs) is the main driver to make network density beneficial to profits. When the seller is able to discriminate between Private and Public WOM, the optimal strategy is to cheaply incentivize the more connected people to pass on the information publicly and then offer a high bonus for Private WOM.

2020 - Facilitating the Decentralised Exchange of Cryptocurrencies in an Order-Driven Market [Relazione in Atti di Convegno]
Platt, Moritz; Pierangeli, Francesco; Livan, Giacomo; Righi, Simone
abstract

This article discusses a protocol to facilitate decentralised exchanges on an order-driven market through a consortium of market services operators. We discuss whether this hybrid protocol combining a centralised initiation phase with a decentralised execution phase outperforms fully centralised exchanges with regards to efficiency and security. Here, a fully efficient and fully secure protocol is defined as one where traders incur no trading costs or opportunity costs and counterparty risk is absent. We devise a protocol addressing the main downsides in the decentralised exchange process that uses a facilitating distributed ledger, maintains an order book and monitors the order status in real-time to provide accurate exchange rate information and performance scoring of participants. We show how performance ratings can lower opportunity costs and how a rolling benchmark rate of verifiable trades can be used to establish a trustworthy exchange rate between cryptocurrencies. The formal validation of the proposed technical mechanisms is the subject of future work.

2020 - Modelling approaches to food waste: Discrete event simulation; machine learning; bayesian networks; agent based simulation; and mass balance estimation [Capitolo/Saggio]
Kandemier, Cansu; Reynolds, Christian; Verma, Monika; Grainger, Matthew; Stewart, Gavin; Righi, Simone; Piras, Simone; Setti, Marco; Vittuari, Matteo; Quested, Tom
abstract

The generation of food waste at both suppliers’ and consumers’ levels stems from a complex set of interacting behaviours. Computational and mathematical models provide various methods to simulate, diagnose and predict different aspects within the complex system of food waste generation and prevention. This chapter outlines four different modelling approaches that have been used previously to investigate food waste. Discrete Event Simulation: which has been used to examine how the shelf life of milk and many actions taken around shopping and use of milk within a household influence food waste. Machine Learning and Bayesian networks: which have been used to provide insight into the determinates of household food waste. Agent Based Simulation: which has been used to provide insight into how innovation can reduce retail food waste. Mass Balance estimation which has been used to model and estimate food waste from data related to human metabolism and calories consumed.

2019 - Behavioural economics: assessing food waste innovations diffusion through ABM models - Insights from Italy and the Netherlands. REFRESH Deliverable 4.5 [Monografia/Trattato scientifico]
Masotti, M.; Piras, S.; Righi, S.; Setti, M.; Aramyan, L.; Logatcheva, K.; Vittuari, M.
abstract

Food Waste is problem related to all the actors of the Food Value Chain: producers, retailers and consumers. In this context, retail sector plays an important role in tackling the food waste problem. Food waste at the retail level can be reduced through the adoption of food waste reducing innovations. The authors investigate the most relevant factors that promote the adoption of those innovations among retailers.

2019 - Detecting multidimensional clustering across EU regions. Focus on R&I smart specialisation strategies and on socio-economic and demographic conditions [Working paper]
Russo, M.; Pavone, P.; Pagliacci, F.; Righi, S.; Giorgi, A.
abstract

This paper applies multidimensional clustering of EU-28 regions to identify similar specialisation strategies and socioeconomic characteristics. It builds on an original dataset where the EU-28 regions are classified according to their socioeconomic and demographic features and to the strategic priorities outlined in their research and innovation smart specialisations strategy (RIS3). The socioeconomic and demographic classification associates each region to one categorical variable (with 19 modalities), while the classification of the RIS3 priorities clustering was performed separately on “descriptions” (21 Boolean categories) and “codes” (11 Boolean Categories) of regions’ RIS3. Three techniques of clustering have been applied: Infomap multilayer algorithm, Correspondence Analysis plus Cluster Analysis and cross tabulation. The most effective clustering, in terms of both the characteristics of the data and the emerging results, is that obtained on the results of the Correspondence Analysis. By contrast, due to the very dense network induced by the data characteristics, the Infomap algorithm does not produce significant results. Finally, cross tabulation is the most detailed tool to identify groups of regions with similar characteristics. In particular, in the paper we present an application of cross tabulation to focus on the regions investing in sustainable development priorities. Policy implications of methods implemented in this paper are discussed as a contribution to the current debate on post-2020 European Cohesion Policy, which aims at orienting public policies toward the reduction of regional disparities and the enhancement of complementarities and synergies within macroregions.

2019 - Innovation Poles in Tuscany 2011-2014 [Banca dati]
Righi, Riccardo; Russo, Margherita; Caloffi, Annalisa; Righi, Simone; Rossi, Federica
abstract

The database "Innovation Poles in Tuscany 2011-2014" collects data on innovation intermediaries, funded through a regional policy intervention, in the Italian region of Tuscany. It has been developed in the research project "Poli.in Analysis and modelling of innovation poles in Tuscany" (www.poliinovazione.unimore.it), co-funded by Tuscany's Regional Administration and University of Modena and Reggio Emilia, Italy. Publications using the present data set are available at www.poliinovazione.unimore.it. The dataset has been already elaborated in - Russo, Margherita, Annalisa Caloffi, Riccardo Righi, Simone Righi, Federica Rossi «Multilayer Network analysis of innovation intermediaries’ activities». In G. Ragozini, M. P. Vitale (eds.), Challenges in Social Network Research, Lecture Notes in Social Networks, © Springer Nature Switzerland AG 2019, https://doi.org/10.1007/978-3-030-31463-7_12 - Russo, Margherita, Annalisa Caloffi, Riccardo Righi, Simone Righi, Federica Rossi. 2016. «Multilayer Network analysis of innovation intermediaries’ activities: methodological issues and an application to a regional policy programme», In Blue Sky Forum: Posters Gallery-Innovation Metrics. Ghent, Belgium. http://www.oecd.org/sti/blue-sky-posters.htm. - Russo, Margherita, Annalisa Caloffi, Federica Rossi, Riccardo Righi. 2018. «Innovation intermediaries and performance-based incentives: a case study of regional innovation poles». Science and Public Policy, 46(1), 2019, 1–12 https://doi.org/10.1093/scipol/scy028. FOLDERS: - folder edges: data on the edgelist in .csv, .dta, .xlsx - folder nodes: data agents in .csv, .dta, .xlsx - folder “graph” : RDS file network in igraph

2019 - Multilayer Network Analysis of Innovation Intermediaries’ Activities [Capitolo/Saggio]
Russo, Margherita; Annalisa, Caloffi; Righi, Riccardo; Righi, Simone; Rossi, Federica
abstract

Policymakers wishing to enhance innovation processes in small and medium-sized enterprises increasingly channel their interventions through innovation intermediaries. However, limited empirical research exists regarding the activities and performance of intermediaries, with most contributions taking a qualitative approach and focusing on the role of intermediaries as brokers. In this paper, we analyse the extent to which innovation intermediaries, through their engagement in different activities, support the creation of communities of other agents. We use multilayer network analysis techniques to simultaneously represent the many types of interactions promoted by intermediaries. Furthermore, by originally applying the Infomap algorithm to our multilayer network, we assess the contribution of the agents involved in different activities promoted by intermediaries, and we identify the emerging multilayer communities and the intercohesive agents that span across several communities. Our analysis highlights the potential and the critical features of multilayer analysis for policy design and evaluation.

2019 - The price of discovering your needs online [Articolo su rivista]
Carroni, E.; Ferrari, L.; Righi, S.
abstract

Web users, even when not actively looking for a product, are continuously targeted by offers that potentially fit their interests. Does this kind of targeting always promote transactions with high social value? We consider a model in which a two-sided platform is visited by sellers seeking to promote their products and by users with state-contingent preferences about those products. Depending on its targeting ability, the platform could be able to target users by tailored advertising banners. We show that persuasion is stronger when targeting ability is maximal, fueling purchases that rational individuals may regret due to the persuasive nature of banners. (C) 2019 The Authors. Published by Elsevier B.V.

2018 - Food waste as a (negative) measure of social capital. A study across Italian Provinces [Working paper]
Piras, S.; Pancotto, F.; Righi, S.; Vittuari, M.; Setti, M.
abstract

Household food waste is a crucial problem in developed countries. Food waste behaviour is the result of complex interactions among economic factors, deeply rooted habits, and social norms. It can thus be considered a measure of the social capital characterizing a community. We test this hypothesis using a national-level dataset on household food-related behaviours and opinions in Italy gathered in 2016. This country is an ideal test bed for a comparative analysis on social capital. We find household food waste measures to be negatively related with the local level of social capital. This relationship is mediated by family income, as it becomes weaker for better-off families. Furthermore, we find that behaviours and opinions eliciting status concerns with respect to food, as well as lack of organisational abilities, generate increased food waste. In turn, these behaviours and opinions are more prevalent in areas with low social capital. Our results, captured by a simple model where food waste decisions are considered in the context of a modified public good game, allow to derive several policy implications for the reduction of food waste.

2018 - Food waste as a (negative) measure of social capital. A study across Italian Provinces [Working paper]
Piras, S.; Pancotto, F.; Righi, S.; Vittuari, M.; Setti, M.
abstract

Household food waste is a crucial problem in developed countries. Food waste behaviour is the result of complex interactions among economic factors, deeply rooted habits, and social norms. It can thus be considered a measure of the social capital characterizing a community. We test this hypothesis using a national-level dataset on household food-related behaviours and opinions in Italy gathered in 2016. This country is an ideal test bed for a comparative analysis on social capital. We find household food waste measures to be negatively related with the local level of social capital. This relationship is mediated by family income, as it becomes weaker for better-o families. Furthermore, we find that behaviours and opinions eliciting status concerns with respect to food, as well as lack of organisational abilities, generate increased food waste. In turn, these behaviours and opinions are more prevalent in areas with low social capital. Our results, captured by a simple model where food waste decisions are considered in the context of a modified public good game, allow to derive several policy implications for the reduction of food waste.

2018 - Model integration. Integrated socio-economic model on food waste [Altro]
Grainger, Matthew; Stewart, Gavin; Piras, Simone; Righi, Simone; Setti, Marco; Vittuari, Matteo
abstract

The model architecture described in this deliverable provides the framework through which data and simulations from the data on food waste at a consumer level and at a retail level can be integrated into simulation models. This report highlights the technical approaches followed to achieve model integration. This report highlights the technical approaches followed to achieve model integration. An integrated whole-of-system modelling approach will be developed as a part of the REFRESH project to allow the development of a decision-relevant, and dynamic policy support tool, by which a road map to the reduction of European food waste by 50% by 2030 can be developed. The vital first step (highlighted in this report) is to develop the structures to allow model integration between different model types: Agent-Based Models and Bayesian Networks. These structures were developed and tested to ensure that the model types can be integrated. The architecture described in this deliverable provides the framework through which data and simulations from the data on food waste at a consumer level and at a retail level can be integrated into simulation models. Since a sizable share of the food waste is generated either at the consumer level or at the interaction between consumers and retailers, we address the modelling effort with two integrated ABM-BN models. The first model reproduces the dynamic evolution of food waste choices of consumers as consequence of social interactions. The second focuses instead on the conditions for the successful diffusion and adoption of innovations to reduce food waste at the retailer level. The systemic modelling approach proposed will allow the development of selected simulation scenarios at the consumer and retail level, facilitating decision making in the face of uncertainty. These integrated setups are first iterations of working integrated models, aimed at validating technically the setups as well as the integration process itself. As they are, there are certainly factors that are likely to be important in determining food waste, which are not yet included in the models. However, the latter are flexible and can accommodate further details, and variables. Their construction is purposefully flexible in terms of components of decisions. The integration with Bayesian Networks ensure that Agent-Based models will learn from data originated from the other refresh WPs and will evolve, allowing the introduction of new variables and factors that will lead to the improvement of the different simulation scenarios. The REFRESH project implements a behavioural economics approach in order to identify and measure the most important socio-economic conditions and potential policy interventions driving businesses’ and consumers’ choices in the generation of food waste. More specifically, this work aims to provide new information on consumer and business behaviour by measuring the effects of major tangible factors of food waste, by identifying hidden and emerging profiles of consumer’ and business’ behaviours affecting food waste, and by allowing the detection of intangible food waste drivers. Such an objective is achieved through the development and the testing of Agent-Based Models (ABMs) and Bayesian networks (BNs).

2018 - Model selection and averaging in the assessment of the drivers of household food waste to reduce the probability of false positives [Articolo su rivista]
James Grainger, Matthew; Aramyan, Lusine; Piras, Simone; Edward Quested, Thomas; Righi, Simone; Setti, Marco; Vittuari, Matteo; Bruce Stewart, Gavin
abstract

Food waste from households contributes the greatest proportion to total food waste in developed countries. Therefore, food waste reduction requires an understanding of the socio-economic (contextual and behavioural) factors that lead to its generation within the household. Addressing such a complex subject calls for sound methodological approaches that until now have been conditioned by the large number of factors involved in waste generation, by the lack of a recognised definition, and by limited available data. This work contributes to food waste generation literature by using one of the largest available datasets that includes data on the objective amount of avoidable household food waste, along with information on a series of socio-economic factors. In order to address one aspect of the complexity of the problem, machine learning algorithms (random forests and boruta) for variable selection integrated with linear modelling, model selection and averaging are implemented. Model selection addresses model structural uncertainty, which is not routinely considered in assessments of food waste in literature. The main drivers of food waste in the home selected in the most parsimonious models include household size, the presence of fussy eaters, employment status, home ownership status, and the local authority. Results, regardless of which variable set the models are run on, point toward large households as being a key target element for food waste reduction interventions.

2018 - Social closure and the evolution of cooperation via Indirect reciprocity [Articolo su rivista]
Righi, Simone; Takács, Károly
abstract

Direct and indirect reciprocity are good candidates to explain the fundamental problem of evolution of cooperation. We explore the conditions under which different types of reciprocity gain dominance and their performances in sustaining cooperation in the PD played on simple networks. We confirm that direct reciprocity gains dominance over indirect reciprocity strategies also in larger populations, as long as it has no memory constraints. In the absence of direct reciprocity, or when its memory is flawed, different forms of indirect reciprocity strategies are able to dominate and to support cooperation. We show that indirect reciprocity relying on social capital inherent in closed triads is the best competitor among them, outperforming indirect reciprocity that uses information from any source. Results hold in a wide range of conditions with different evolutionary update rules, extent of evolutionary pressure, initial conditions, population size, and density.

2018 - The use of systems models to identify food waste drivers [Articolo su rivista]
Grainger, Matthew James; Aramyan, Lusine; Logatcheva, Katja; Piras, Simone; Righi, Simone; Setti, Marco; Vittuari, Matteo; Stewart, Gavin Bruce
abstract

In developed countries, the largest share of food waste is produced at household level. Most studies on consumers’ food waste use models that identify covariates as significant when in fact they may not be, particularly where these models use many variables. Here, relying on EU-level Eurobarometer data from 2013, we use alternative analytical methods that avoid these problems (Bayesian Networks) to identify the impact of household characteristics and other variables on self-assessed food waste. Our analysis confirms that the country, the age of the respondent, the status (student/non-student), and a belief that the family wastes too much are related to the level of self-assessed food waste. But we found no evidence that waste behaviours differ between people living in urban and rural areas, and little support of a difference between genders. Households from lower-income EU countries (e.g. Portugal, Greece, Bulgaria, Cyprus and Latvia), as well as students and young adults tend to report higher levels of food waste. Hence, the adoption of an EU strategy based on the concept of subsidiarity, and of country-level policy measures targeting different age groups is suggested. Furthermore, our analysis shows that policy makers need to be wary of relying on analysis based on large datasets that do not control for false-positives, particularly when sample sizes are small.

2017 - Blind vs. embedded indirect reciprocity and the evolution of cooperation [Relazione in Atti di Convegno]
Righi, Simone; Takács, Károly
abstract

The evolution of cooperation is one of the fundamental problems of both social sciences and biology. It is difficult to explain how a large extent of cooperation could evolve if individual free riding always provides higher benefits and chances of survival. In absence of direct reciprocation, it has been suggested that indirect reciprocity could potentially solve the problem of large scale cooperation. In this paper, we compare the chances of two forms of indirect reciprocity with each other: a blind one that rewards any partner who did good to previous partners, and an embedded one that conditions cooperation on good acts towards common acquaintances. We show that these two versions of indirect reciprocal strategies are not very different from each other in their efficiency. We also demonstrate that their success very much relies on the speed of evolution: their chances for survival are only present if evolutionary updates are not frequent. Robustness tests are provided for various forms of biases.

2017 - Parallel versus Sequential Update and the Evolution of Cooperation with the Assistance of Emotional Strategies [Capitolo/Saggio]
Righi, Simone; Karoly, Takacs
abstract

Our study contributes to the debate on the evolution of cooperation in the single shot Prisoner’s Dilemma (PD) played on networks. We construct a model in which individuals are connected with positive and negative ties. Some agents play sign-dependent strategies that use the sign of the relation as a shorthand for determining appropriate action toward the opponent. In the context of our model in which network topology, agent strategic types and relational signs coevolve, the presence of sign-dependent strategies catalyzes the evolution of cooperation. We highlight how the success of cooperation depends on a crucial aspect of implementation: whether we apply parallel or sequential strategy update. Parallel updating, with averaging of payoffs across interactions in the social neighborhood, supports cooperation in a much wider set of parameter values than sequential updating. Our results cast doubts about the realism and generalizability of models that claim to explain the evolution of cooperation but implicitly assume parallel updating.

2017 - Reflexivity reduces pro-sociality but only among strategic subjects [Working paper]
Codeluppi, F.; Pancotto, F.; Righi, S.
abstract

Is pro-sociality a natural impulse or the result of a self-controlled behavior? The literature is not quite univocal on the cognitive mechanisms behind this key feature of observed human behavior. We investigate this issue in a lab in the field experiment with participants selected among the general adult population in Italy. We test prosociality with a Distribution game (or three player dictator game), reflexive versus impulsive behavior with an extended version of the Cognitive Reflection Test and strategic reasoning with the guessing game. In the latter, we request to participants to provide also a motivation of the choice they made in the game. We find two important results: first, that there is a positive relationship between pro-sociality and strategic reasoning. Second, reflexivity reduces pro-sociality but only among strategic subjects. Our results support the intuitive view of pro-sociality: naive individuals that do not control their impulses behave pro-socially, while among strategic subjects the ability to suppress the pro-social impulse is achieved by those subjects making a more selfcontrolled and reflexive choice.

2016 - Enhancing the resilience of social infrastructures: issues on agents, artefacts and processes. Proceedings of the 2016 Modena Workshop [Working paper]
Russo, M.; Pagliacci, F.; Righi, S.
abstract

In the social sciences domain, the term 'resilience' is usually associated to a wide set of changes that affect people and their communities. In particular, both the Hyogo Framework for Action 2005–2015 and the Sendai Framework explicitly focus on the way in which communities face both natural and man-made hazards. To this respect, both material and non-material infra-structures play a critical role, hence deserving a specific focus when assessing local communities' level of resilience. Among them, this paper focuses on: health services, social services, govern-ment (according to a multi-level perspective, from the national to the local level), communication infrastructure (i.e. specific tools to interconnect all aforementioned networks). Firstly, this paper discusses some of the most important issues and theoretical frameworks that should be addressed in the analysis of the processes of enhancing the resilience of social infrastructures. Secondly, the discussion that took place in a workshop promoted in May 2016 as the outcome of a one-year dialogue across a group of EU researchers is returned. The debate moves from some theoretical perspectives on resilience and it eventually returns some case studies and real experiences, such as the actions of local governments and the role of risk communication.

2016 - Enhancing the resilience of social infrastructures: issues on agents, artefacts and processes. Proceedings of the 2016 Modena Workshop [Working paper]
Pagliacci, F.; Righi, S.; Russo, M.
abstract

In the social sciences domain, the term 'resilience' is usually associated to a wide set of changes that affect people and their communities. In particular, both the Hyogo Framework for Action 2005–2015 and the Sendai Framework explicitly focus on the way in which communities face both natural and man-made hazards. To this respect, both material and non-material infrastructures play a critical role, hence deserving a specific focus when assessing local communities' level of resilience. Among them, this paper focuses on: health services, social services, government (according to a multi-level perspective, from the national to the local level), communication infrastructure (i.e. specific tools to interconnect all aforementioned networks). Firstly, this paper discusses some of the most important issues and theoretical frameworks that should be addressed in the analysis of the processes of enhancing the resilience of social infrastructures. Secondly, the discussion that took place in a workshop promoted in May 2016 as the outcome of a one-year dialogue across a group of EU researchers is returned. The debate moves from some theoretical perspectives on resilience and it eventually returns some case studies and real experiences, such as the actions of local governments and the role of risk communication.

2016 - Miracle of Peer Review and Development in Science: An Agent-Based Model [Working paper]
Righi, S.; Takacs, K.
abstract

It is not easy to rationalize how peer review, as the current grassroots of science, can work based on voluntary contributions of reviewers. There is no rationale to write impartial and thorough evaluations. Consequently, there is no risk in submitting lowquality work by authors. As a result, scientists face a social dilemma: if everyone acts according to his or her own self-interest, low scienti c quality is produced. Still, in practice, reviewers as well as authors invest high e ort in reviews and submissions. We examine how the increased relevance of public good bene ts (journal impact factor), the editorial policy of handling incoming reviews, and the acceptance decisions that take into account reputational information can help the evolution of high-quality contributions from authors. High e ort from the side of reviewers is problematic even if authors cooperate: reviewers are still best o by producing low-quality reviews, which does not hinder scienti c development, just adds random noise and unnecessary costs to it. We show with agent-based simulations that tacit agreements between authors that are based on reciprocity might decrease these costs, but does not result in superior scienti c quality. Our study underlines why certain self-emerged current practices, such as the increased importance of journal metrics, the reputation-based selection of reviewers, and the reputation bias in acceptance work e ciently for scienti c development. Our results nd no answers, however, how the system of peer review with impartial and thorough evaluations could be sustainable jointly with rapid scienti c development

2016 - Model Development and Data Protocol [Altro]
Grainger, Matthew; Crichton, GAVIN STEWART; Piras, Simone; Righi, Simone; Setti, Marco; Vittuari, Matteo
abstract

The generation of food waste stems from a complex set of interacting behaviours of both food consumers and suppliers. Therefore, a complete approach to the problem requires an analysis of both sources of waste. Both Agent Based Models and Bayesian Networks provide a modelling approach that fits this purpose, since they allow the study of complex systems. WP4 of the REFRESH project implements a behavioural economics approach in order to identify and measure the most important socio-economic conditions and potential policy interventions driving businesses’ and consumers’ choices in the generation of food waste. More specifically WP4 aims to provide new information on consumer and business behaviour by measuring the effects of major tangible factors of food waste, by identifying hidden and emerging profiles of consumer’ and business’ behaviours affecting food waste, and by allowing the detection of intangible food waste drivers. Such an objective is achieved through the development and the testing of Agent-Based Models (ABMs) and Bayesian networks (BNs). The report is structured as follows: Chapter 3 defines what a model is and the modelling approaches that will be utilized within REFRESH WP4. Chapters 4 and 5 illustrate the characteristics of ABMs and BNs. Chapter 6 outlines an ABM aimed at assessing the adoption of innovations for preventing or reducing the food waste generated by companies of the retail sector. Chapter 7 outlines a BN for characterizing consumers’ behaviour with respect to food waste. Chapter 8 anticipates potential modes of interaction between ABMs and BNs. Chapter 9 identifies a number of good practices to ensure effective data management and facilitate data exchange.

2016 - Multilayer network analysis of innovation intermediaries’ activities: methodological issues and an application to a regional policy programme [Poster]
Russo, Margherita; Annalisa, Caloffi; Righi, Riccardo; Righi, Simone; Rossi, Federica
abstract

To enhance innovation processes in small and medium-sized enterprises (SMEs), in the last decade innovation policies have increasingly supported the creation and strengthening of intermediaries (Howells, 2006; Lazaric et al, 2008; Kauffeld-Monz and Fritsch, 2013; Russo and Rossi, 2009; Caloffi et al, 2015). So far, however no adequate analytical framework to assess the activity and performance of these intermediaries has been developed. In this paper we address this issue by suggesting a network perspective (a) to analyse the multidimensional activities undertaken by innovation intermediaries and (b) to assess the contribution of the agents involved in different activities promoted by intermediaries. Methodological issues are discussed both in theory and with regard to an empirical application to analyse a regional policy supporting the creation of specialized intermediaries, named “innovation poles”, in the Italian region of Tuscany. The creation of innovation poles has mobilized a large number of agents that were directly involved with different roles in the creation of the regional system of technology transfer. Through the different activities they perform, the various agents create connections between the poles; the poles, in turn, create links between agents, facilitating the exchange of information and creating opportunities for joint actions to boost innovation. This network of networks perspective of analysis asks for the identification of pivotal agents embedded in multidimensional interactions and helps in detecting emerging communities of innovators in the regional innovation system. By adopting the analysis of multilayer networks approach (recently developed by Rosvall & Bergstrom, 2007 and 2008, and De Domenico et al., 2015), we identify the emerging multilayer communities and the intercohesive agents, framing the intermediaries’ impact. The paper concludes discussing the implications of this methodology on policy assessment.

2016 - Socio-economic implications of food waste: Business behavioural typologies and interrelationships [Altro]
Piras, Simone; Righi, Simone; Setti, Marco; Vittuari, Matteo
abstract

This report aims at identifying behavioural economic interrelationships and typologies that influence the adoption of innovations by businesses. The most important interrelationships and typologies identified will be included within an Agent-Based Model (ABM) aimed at assessing the likelihood of food businesses to create or adopt innovations for preventing (or reducing) food waste. This model will be used later in the project to analyse business behaviours. Standard economic theory postulates that possible social benefits granted by an innovation that targets food waste would not increase businesses’ propensity to adopt it, as firms seen as are rational, selfish, and not affected by social relations. Behavioural economics provides convincing evidence that real-world businesses deviate from the predictions of standard economic theory. Behavioural typologies indicate specific psychological factors that, beyond economic aspects, may affect the adoption of innovations by food companies, either as a driver or as a barrier. A literature review was systematically carried out in order to identify the main business behavioural typologies and interrelationships. These were then grouped into three categories, depending on the specific assumption of standard economic theory they challenge: that of rationality of economic agents, of selfishness, or of irrelevance of the social environment where they operate. For each category, a number of subcategories were identified, and the main stylized facts described. Non-rational firms show limited foresight and, therefore, adaptive expectations, are systematically biased in their process of processing information, react to uncertainty and risk according to the assumptions of prospect theory, and are time-inconsistent. Non-selfish businesses implement satisficing behaviours rather than standard profit maximisation, are influenced by values (such as pro-environmental ones), beliefs and norms, and may act pro-socially (altruistically), because they care about the well-being of others. Relevance of the social environment implies that businesses tend to trust or distrust, are concerned about the fairness of decisions and their distributional outcomes, tend to assess their position with respect to peers, implement reciprocal behaviours, try to build a positive reputation, and coordinate among them, e.g. through alliances or networks. Overall, the adoption of innovations aimed at addressing food waste emerged as a multidimensional phenomenon, and implies high uncertainty. The behaviour of every single business results from its idiosyncratic characteristics, its structural and managerial features, and the environment where they operate. Uncertainty may be addressed by sharing information, or through inter-firm coordination. Focusing on food processors and retailers, behavioural typologies correspond roughly to structural typologies. Two structural typologies can be identified: large businesses (e.g., publically traded processors, large-scale retailers) implement indirect reciprocity, favour formal coordination schemes, and tend to create innovations or to be early adopters; small firms (e.g., local processors, family businesses, traditional shops) resort to satisficing behaviour and prefer to imitate the innovation patterns of their most successful peers, thus complying later or partially with food regulations.

2016 - The Miracle of Peer Review and Development inScience: An Agent-Based Model [Working paper]
Righi, S.; Takacs, K.
abstract

It is not easy to rationalize how peer review, as the current grassroots of science, can work based on voluntary contributions of reviewers. There is no rationale to write impartial and thorough evaluations. Consequently, there is no risk in submitting lowquality work by authors. As a result, scientists face a social dilemma: if everyone acts according to his or her own self-interest, low scientific quality is produced. Still, in practice, reviewers as well as authors invest high effort in reviews and submissions. We examine how the increased relevance of public good benefits (journal impact factor), the editorial policy of handling incoming reviews, and the acceptance decisions that take into account reputational information can help the evolution of high-quality contributions from authors. High effort from the side of reviewers is problematic even if authors cooperate: reviewers are still best off by producing low-quality reviews, which does not hinder scientific development, just adds random noise and unnecessary costs to it. We show with agent-based simulations that tacit agreements between authors that are based on reciprocity might decrease these costs, but does not result in superior scientific quality. Our study underlines why certain self-emerged current practices, such as the increased importance of journal metrics, the reputation-based selection of reviewers, and the reputation bias in acceptance work efficiently for scientific development. Our results find no answers, however, how the system of peer review with impartial and thorough evaluations could be sustainable jointly with rapid scientific development.

2016 - What does the financial market pricing do? A simulation analysis with a view to systemic volatility, exuberance and vagary [Articolo su rivista]
Biondi, Yuri; Righi, Simone
abstract

Biondi et al. (Phys A 391(22):5532–5545, 2012) develop an analytical model to examine the emergent dynamic properties of share market price formation over time, capable to capture important stylized facts. These latter properties prove to be sensitive to regulatory regimes for fundamental information provision, as well as to market confidence conditions among actual and potential investors. We comparatively assess accounting models belonging to two main families: historical cost accounting and mark-to-market (fair value) accounting regimes. Regimes based upon mark-to-market measurement of traded security, while generating higher linear correlation between market prices and fundamental signals, also involve higher market instability and volatility. These regimes also incur more relevant episodes of market exuberance and vagary in some regions of the market confidence space, where lower market liquidity further occurs.

2015 - Campaign Spending and Rents in a Probabilistic Voting Model [Working paper]
Righi, S.
abstract

How the levels of corruption and embezzlement of a political system are influenced by electoral campaigns? How rent extraction can be reduced with anti-corruption policies? We answer these questions in the context of a probabilistic voting model characterized by the absence of political pressure groups and by the presence of ideological voters whose preferences can be manipulated by political candidates through campaign spending. Our main innovation is the introduction of an analysis of candidates’ campaign choices in the literature on the agency costs of political delegation. Moreover, we contribute to the literature establishing a direct link between campaign expenditures and the utility of the voters. We find that campaigning choices are orthogonal to decisions about rent extractions and that candidates always invest a significative amount of their resources of their expected rents in advertisements. As the electoral competition itself does not suffices to reach an efficient outcome, we then study how welfare policies can reduce the inefficiencies of the electoral competition. We show that limitations of campaign expenditures are, in absence of lobbies, always welfare decreasing for voters. Indeed, our main policy suggestion is to introduce an anti-corruption, i.e. a policy that reduces the ability of candidates to extract rents by abating the incentives to rent accumulation. We show that the introduction of such tax can make the citizens better off. Surprisingly, it may also make the candidates better off if the policy is not sufficiently funded. Finally, we establish the conditions under which a policy of this kind can achieve the popular support required for an effective implementation and we show that these conditions are difficult to achieve in countries with large income inequalities.

2015 - Emerging communities in multilayers networks: analysis of a regional policy programme [Poster]
Russo, Margherita; Annalisa, Caloffi; Righi, Riccardo; Righi, Simone; Rossi, Federica
abstract

With the growing importance of policies sponsoring innovation intermediaries (Howells, 2006; Lazaric et al, 2008; Kauffeld-Monz and Fritsch, 2013; Russo and Rossi, 2009; Caloffi et al, 2015), a need has emerged for appropriate instruments to analyze their activity. In general, current approaches do not adopt a network perspective to highlight the multidimensional system created through the activities undertaken by the intermediaries. In this paper we present an empirical analysis of a regional policy supporting the creation of specialized intermediaries in the Italian region of Tuscany. In the programming period 2007-2013 (effectively starting from 2010), the regional government of Tuscany funded twelve ‘innovation poles’. They are regional innovation intermediaries (organized to provide a range of services, including brokering and matchmaking) that bring together a number of universities and innovative service providers with potential end-users of these services. Their main goal is to promote linkages between regional actors: universities, public research organizations, KIBS, large businesses and SMEs. We highlight two main domains of interactions that support the entire system of the poles. The first domain is that in which we find the agents promoting the system of poles: this network involves both the organizations directly managing the poles, through the creation of temporary associations, and the organizations who have shareholdings in those managing organizations. The second domain relates to competence networks initiated by the system of the poles not only through the provision of services by the various operators, but also through the skills of employees and consultants, the collaboration agreements with parties outside the poles, and through the facilities of laboratories and incubators. By creating such multilayer networks we focus on interrelations between the poles based on the activities, undertaken jointly, in supporting the member companies. For each of these domains we examine the characteristics of the networks and the centrality index of the agents involved. Moreover, by adopting the analysis of multilayer networks (recently developed by De Domenico et al., 2015), we identify and compare the emerging communities in aggregate networks and in the multilayer networks with regard to the networks promoting the poles and in the competence networks.

2015 - Inequality, mobility and the financial accumulation process: A computational economic analysis [Working paper]
Biondi, Y.; Righi, S.
abstract

Our computational economic analysis investigates the relationship between inequality, mobility and the financial accumulation process. Extending the baseline model by Levy et al., we characterise the economic process trough stylised return structures generating alternative evolutions of income and wealth through historical time. First we explore the limited heuristic contribution of one and two factors models comprising one single stock (capital wealth) and one single flow factor (labour) as pure drivers of income and wealth generation and allocation over time. Then we introduce heuristic modes of taxation in line with the baseline approach. Our computational economic analysis corroborates that the financial accumulation process featuring compound returns plays a significant role as source of inequality, while institutional configurations including taxation play a significant role in framing and shaping the aggregate economic process that evolves over socioeconomic space and time.

2015 - Much ado about making money: The impact of disclosure, news and rumors over the formation of security market prices over time [Working paper]
Biondi, Y.; Righi, S.
abstract

This article develops an agent-based model of security market pricing process, capable to capture main stylised facts. It features a collective market pricing mechanism based upon evolving heterogenous expectations that incorporate signals of security issuer fundamental performance over time. Distinctive signaling sources on this performance correspond to institutional mechanisms of information diffusion. These sources differ by duration effect (temporary, persistent, and permanent), confidence, and diffusion degree among investors over space and time. Under full and immediate diffusion and balanced reaction by all the investors, the value of these sources should be consistently and timely integrated by the market price process, implying efficient pricing. By relaxing these quite heroic conditions, we assess the impact of distinctive information sources over market price dynamics, through financial systemic properties such as market price volatility, exuberance and errancy, as well as market liquidity. Our simulation analysis shows that transient information shocks can have permanent effects through mismatching reactions and self-reinforcing feedbacks, involving mispricing in both value and timing relative to the efficient market price series. This mispricing depends on both the information diffusion process and the ongoing information confidence mood among investors over space and time. We illustrate our results through paradigmatic cases of stochastic news, before generalising them to autocorrelated news. Our results are further corroborated by robustness checks over the parameter space.

2014 - Degree variance and emotional strategies catalyze cooperation in dynamic signed networks [Relazione in Atti di Convegno]
Righi, Simone; Takács, Károly
abstract

We study the problem of the emergence of cooperation in dynamic signed networks where agent strategies coevolve with relational signs and network topology. Running simulations based on an agent-based model, we compare results obtained in a regular lattice initialization with those obtained on a comparable random network initialization. We show that the increased degree heterogeneity at the outset enlarges the parametric conditions in which cooperation survives in the long run. Furthermore, we show how the presence of sign-dependent emotional strategies catalyze the evolution of cooperation with both network topology initializations.

2014 - Emotional strategies as catalysts for cooperation in signed networks [Articolo su rivista]
Righi, Simone; Takács, Károly
abstract

The evolution of unconditional cooperation is one of the fundamental problems in science. A new solution is proposed to solve this puzzle. We treat this issue with an evolutionary model in which agents play the Prisoner's Dilemma on signed networks. The topology is allowed to co-evolve with relational signs as well as with agent strategies. We introduce a strategy that is conditional on the emotional content embedded in network signs. We show that this strategy acts as a catalyst and creates favorable conditions for the spread of unconditional cooperation. In line with the literature, we found evidence that the evolution of cooperation most likely occurs in networks with relatively high chances of rewiring and with low likelihood of strategy adoption. While a low likelihood of rewiring enhances cooperation, a very high likelihood seems to limit its diffusion. Furthermore, unlike in nonsigned networks, cooperation becomes more prevalent in denser topologies.

2014 - Triadic Balance and Closure as Drivers of the Evolution of Cooperation [Relazione in Atti di Convegno]
Righi, Simone; Takacs, Karoly
abstract

The prevalence of human cooperation continues to be one of the biggest puzzles for scientists. Structured interactions and clustering of cooperators are recognized mechanisms that help the dissemination of cooperative behavior. We analyze two dynamic micro structural mechanisms that may contribute to the evolution of cooperation. We concentrate on two mechanisms that have empirical justification: triadic closure and triadic balance. We study their relative efficiency under different parametric conditions, assuming that the structure of interactions itself might change endogenously as a result of previous encounters.

2013 - Face-to-face discussions: networking or opinions exchange? [Relazione in Atti di Convegno]
Righi, Simone; Carletti, Timoteo
abstract

We use recent results of [4] on face-to-face contact durations to try to answer the question: why do people engage in face-to-face discussions? In particular we focus on behavior of scientists in academic conferences. We show evidence that macroscopic measured data are compatible with two different micro-founded models of social interaction. We find that the first model, in which discussions are performed with the aim of introducing oneself (networking), explains the data when the group exhibits few well reputed scientists. On the contrary, when the reputation hierarchy is not strong, a model where agents’ encounters are aimed at exchanging opinions explains the data better.

2013 - Review of "Decoding Complexity: Uncovering Patterns in Economic Networks" by James Grattfelder [Recensione in Rivista]
Righi, Simone
abstract

Review of "Decoding Complexity: Uncovering Patterns in Economic Networks" by James Grattfelder

2013 - Signed Networks, Triadic Interactions and the Evolution of Cooperation [Abstract in Atti di Convegno]
Righi, Simone; Takács, Károly
abstract

We outline a model to study the evolution of cooperation in a population of agents playing the prisoner's dilemma in signed networks. We highlight that if only dyadic interactions are taken into account, cooperation never evolves. However, when triadic considerations are introduced, a window of opportunity for emergence of cooperation as a stable behaviour emerges.

2012 - Behavioral Biases and Informational Inefficiency in an Agent-Based Financial Market [Relazione in Atti di Convegno]
Righi, Simone; Carletti, Timoteo; Aldashev, Gani
abstract

The role of competitive markets as efficient aggregators of decentralized information is a fundamental problem in economic theory. This paper studies the informational efficiency of a market with a single traded asset, in which agents expectation formation about future price has two kinds of deviations from rationality. First, traders have adaptive expectations, i.e. they give more importance to the past price than a rational agent. Second, the agents are subject to the confirmatory bias, i.e. they tend to discard new information that substantially differs from their priors. Taken separately, each deviation worsens the informational efficiency of the market. However, for some ranges of parameters, when the two biases are combined, they tend to mitigate each other effect (thus increasing the informational efficiency). We also study the robustness of these findings to alternative specifications concerning market participation, entry of new agents, and the amount of liquidity that agents hold.

2011 - Emerging structures in social networks guided by opinions' exchanges [Articolo su rivista]
Carletti, Timoteo; Righi, Simone; Fanelli, Duccio
abstract

In this paper, we show that the small world and weak ties phenomena can spontaneously emerge in a social network of interacting agents. This dynamics is simulated in the framework of a simplified model of opinion diffusion in an evolving social network where agents are made to interact, possibly update their beliefs and modify the social relationships according to the opinion exchange.

2011 - Follies subdued: Informational efficiency under adaptive expectations and confirmatory bias [Articolo su rivista]
Aldashev, Gani; Carletti, Timoteo; Righi, Simone
abstract

We study the informational efficiency of a market with a single traded asset. The price initially differs from the fundamental value, about which the agents have noisy private information (which is, on average, correct). A fraction of traders revise their price expectations in each period. The price at which the asset is traded is public information. The agents' expectations have an adaptive component and a social-interactions component with confirmatory bias. We show that, taken separately, each of the deviations from rationality worsens the informational efficiency of the market. However, when the two biases are combined, the degree of informational inefficiency of the market (measured as the deviation of the long-run market price from the fundamental value of the asset) can be non-monotonic both in the weight of the adaptive component and in the degree of confirmatory bias. For some ranges of parameters, two biases tend to mitigate each other's effect, thus increasing informational efficiency.

2010 - Weighted Fractal Networks [Articolo su rivista]
Carletti, Timoteo; Righi, Simone
abstract

In this paper we define a new class of weighted complex networks sharing several properties with fractal sets, and whose topology can be completely analytically characterized in terms of the involved parameters and of the fractal dimension. General networks with fractal or hierarchical structures can be set in the proposed framework that moreover could be used to provide some answers to the widespread emergence of fractal structures in nature.

2009 - How Opinion Dynamics Shapes Social Networks Topology [Relazione in Atti di Convegno]
Righi, Simone; Carletti, Timoteo
abstract

We investigate an opinion dynamics model with continuously defined affinities and opinions. We focus here on the effects of the social network’s topology on the dynamical evolution and on the scale properties of the model measured through numerical simulations and fittings. We study different network topologies through a set of statistical network measures, namely mean path, mean degree and clustering. We observe that the model’s dynamics eventually leads to a uniformization of the different topologies.

2009 - The influence of social network topology in a opinion dynamics model [Relazione in Atti di Convegno]
Righi, Simone; Carletti, Timoteo
abstract

We investigate an opinion dynamics model with continuously defined affinities and opinions. We focus here on the effects of the social network’s topology on the dynamical evolution and on the scale properties of the model measured through numerical simulations and fittings. We study different network topologies through a set of statistical network measures, namely mean path, mean degree and clustering. We observe that the model’s dynamics eventually leads to a uniformization of the different topologies.

2008 - Evaluating Project Communications with social network Analysis, [Capitolo/Saggio]
Dall, Elke; Righi, Simone
abstract

The case study presented describes the use of the methodology of Social Network Analysis (SNA) for internal evaluation and analysis of (international) inter-institutional project communications. The centre for Social Innovation (ZSI) has gained positive experiences with this methodology in the Leonardo pilot project CETRA (Complexity Education for Trainers). This paper describes how the methodology can be used and possible results. The analyzed project developed over time in a cooperation network centered on the coordinator which clearly reflected the strategy implemented. Different roles of partners can be identified and discussed; communication problems (e.g. free rider) can be identified. This methodology can be transferred in different contexts and it is recommended as a tool for internal evaluation flows in any kind of project.

2008 - Shaping Opinions in a Social Network [Relazione in Atti di Convegno]
Righi, Simone; Carletti, Timoteo
abstract

We hereby propose a model of opinion dynamics where individuals update their beliefs because of interactions in acquaintances’ group. The model exhibit a non trivial behavior that we discuss as a function of the main involved parameters. Results are reported on the average number of opinion clusters and the time needed to form such clusters.

2007 - Complexity and Innovation [Capitolo/Saggio]
Righi, Simone
abstract

Not present