This model is a replication of that described by Peterson (2002) and illustrates the ‘spread’ feedback loop type described in Millington (2013).

This generic agent-based model simulates the evolution of agent’s opinions through their exchange of arguments.
The idea behind this model is to explicitly represent the process of mental deliberation of agents from arguments to an opinion, through the use of Dung’s argumentation framework complemented by a structured description of arguments. An application of the model on the diffusion of vegetarian diets is proposed.

The basic idea behind developing MIXTRUST was to represent a network of agricultural stakeholders composed of farmers and a cooperative in a mixed landscape to test its performances in response to risks. A mixed landscape here is a landscape where crop and livestock systems interact by the intermediary of material flows of agricultural products. It can be within mixed farms, or between farms, often specialized, (e.g. straw-manure).

We build a computational model to investigate, in an evolutionary setting, a series of questions pertaining to happiness.

An agent-based model of the scapegoat mechanism of René Girard’s mimetic theory on a coevolving network. Agents accumulate tension from a shared stressor and from contagion; an agent whose whole neighbourhood is saturated accuses another; ties reorganise around accusers; once the marked exceed a tenth of the living, a threshold rule expels one of them and the group’s tension is discharged. The model asks when a stressed population reaches the collective act, what it costs and what it leaves behind: without the accusation rules tension saturates and most of the population dies; with them tension stays low and the cost falls on a few; closure (the reluctance to form new ties) decides whether expulsion occurs and skepticism decides when; the act’s lasting mark is a lower division into communities. A null model, the ablation of each rule, six initial networks and controls on the reach of the relief test the results. Release 1.1.0 is the package behind a manuscript submitted to JASSS (November 2026): six model versions, the per-tick output of every series, daily aggregates of eight anonymised episodes of online hostility and the scripts that regenerate every table and figure. Releases 1.0.x hold an earlier version of the model alone.

This model simulates the emergence of a dual market structure from firm-level interaction. Firms are profit-seeking, and demand is represented by a unimodal distribution of consumers along a set of taste positions.

This a model developed as a part of the paper Mejía, G. & García-Díaz, C. (2018). Market-level effects of firm-level adaptation and intermediation in networked markets of fresh foods: a case study in Colombia. Agricultural Systems 160: 132-142.

It simulates the competition dynamics of the potato market in Bogotá, Colombia. The model explores the economic impact of intermediary actors on the potato supply chain.

This model inspects the performance of firms as the product attribute space changes, which evolves as a consequence of firms’ actions. Firms may create new product variants by dragging demand from other existing variants. Firms decide whether to open new product variants, to invade existing ones, or to keep their variant portfolio. At each variant there is a Cournot competition each round. Competition is nested since many firms compete at many variants simultaneously, affecting firm composition at each location (variant).

After the Cournot outcomes, at each round firms decide whether to (i) keep their existing product variant niche, (ii) invade an existing variant, (iii) create a new variant, or (iv) abandon a variant. Firms’ profits across their niche take into consideration the niche-width cost and the cost of opening a new variant.

Agent-based models of organizational search have long investigated how exploitative and exploratory behaviors shape and affect performance on complex landscapes. To explore this further, we build a series of models where agents have different levels of expertise and cognitive capabilities, so they must rely on each other’s knowledge to navigate the landscape. Model A investigates performance results for efficient and inefficient networks. Building on Model B, it adds individual-level cognitive diversity and interaction based on knowledge similarity. Model C then explores the performance implications of coordination spaces. Results show that totally connected networks outperform both hierarchical and clustered network structures when there are clear signals to detect neighbor performance. However, this pattern is reversed when agents must rely on experiential search and follow a path-dependent exploration pattern.

The model represents a large, traditional firm competing with small, sustainable food producers. The large firm operates under conventional assumptions, pursuing monopoly profits maximized through standard economic principles. Its behavior is driven by economies of scale, which compel small firms to strategically differentiate themselves to deliver added value to consumers. Consequently, small firms focus on offering higher-quality products—a factor that matters significantly to consumers.

The gains achieved by small firms represent social profits that hinge upon establishing co-participation schemes with farmers and building trustworthy relationships with consumers. Cooperation with farmers directly shapes production processes and product quality. Because a firm trusted by one consumer becomes visible to neighbors, trust can diffuse and evolve into a collective identity. Ultimately, population-level legitimation occurs when the organizational form of the organic food producer gains widespread acceptance within the consumer community.

The model’s behavior depends on three key factors: a trust parameter, a legitimation intensity parameter, and an aspiration-level weight (for the large firm).