Is the mass shooter a maniac or a relatively normal person in a state of great stress? According to the FBI report (Silver, J., Simons, A., & Craun, S. (2018). A Study of the Pre-Attack Behaviors of Active Shooters in the United States Between 2000 – 2013. Federal Bureau of Investigation, U.S. Department of Justice,Washington, D.C. 20535.), only 25% of the active shooters were known to have been diagnosed by a mental health professional with a mental illness of any kind prior to the offense.
The main objects of the model are the humans and the guns. The main factors influencing behavior are the population size, the number of people with mental disabilities (“psycho” in the model terminology) per 100,000 population, the total number of weapons (“guns”) in the population, the availability of guns for humans, the intensity of stressors affecting humans and the threshold level of stress, upon reaching which a person commits an act of mass shooting.
The key difference (in the model) between a normal person and a psycho is that a psycho accumulates stressors and, upon reaching a threshold level, commits an act of mass shooting. A normal person is exposed to stressors, but reaching the threshold level for killing occurs only when the simultaneous effect of stressors on him exceeds this level.
The population dynamics are determined by the following factors: average (normally distributed) life expectancy (“life_span” attribute of humans) and population growth with the percentage of newborns set by the value of the TickReprRatio% slider of the current population volume from 16 to 45 years old.Thus, one step of model time corresponds to a year.

This model illustrates actor interaction in the construction sector, according to information gathered in NL. It offers a simple frame to represent diverse interests, interdependencies and effects on the number of built sustainable houses.

The my-side bias is a well-documented cognitive bias in the evaluation of arguments, in which reasoners in a discussion tend to overvalue arguments that confirm their prior beliefs, while undervaluing arguments that attack their prior beliefs. This agent-based model in Netlogo simulates a group discussion among myside-biased agents, within a Bayesian setting. This model is designed to investigate the effects of the myside bias on the ability of groups to reach a consensus or collectively track the correct answer to a given binary issue.

Model explains both the final state and the dynamics of the development process of the wine sector in the Małopolska region in Poland. Model admits heterogeneous agents (regular farms,large and small vineyards).

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).

This is a stationarity test, it tests whether a given moment is constant during the time series (null hypothesis). The Wald Wolfowitz nonparametric fitness test is applied to time series.

Flibs’NLogo is an agent-based simulation implemented in NetLogo that models the evolution of perfect predictors through a genetic algorithm. The agents, called flibs (finite living blobs), are finite‑state automata whose behaviour is encoded in circular chromosomes. They inhabit a “primordial computer soup” and are tasked with anticipating a user‑defined periodic binary sequence. Each generation consists of 100 evaluation cycles, during which a flib’s fitness is incremented each time its output correctly matches the next environmental signal.
Reproduction follows an elitist scheme: a donor (current fittest individual) replaces a randomly chosen recipient either by cloning (complete genome substitution) or by bacterial‑like conjugation (unidirectional horizontal transfer of a random chromosome segment). A stochastic mutagenesis operator introduces point mutations in genes, while the reproductive strategy gene can also switch under a mixed-reproduction regime. Population dynamics are monitored via genomic diversity indices (Shannon‑Wiener, Simpson), a phenotypic simpleness metric that distinguishes the low number of states actually used from the genomic potential.
The model serves as a digital evolutionary laboratory for exploring the interplay among bounded rationality, collective adaptation, and the emergence of anticipatory behaviour. By linking evolutionary computation with cognitive concepts, Flibs’NLogo investigates fundamental transitions from reactive to predictive systems and allows for testing whether populations evolve toward minimal necessary complexity or exhibit an intrinsic drift toward structural elaboration.

This model is a small extension (rectangular layout) of Joshua Epstein’s (2001) model on development of thoughtless conformity in an artificial society of agents.

The network-based trust game is a hybridization of both the repeated trust games and the network games.

This model simulate product diffusion on different social network structures.