In the Bonabeau model, chemotaxis, which is observed in social insects, such as ants, was introduced into the movement rules of agents to control the collision frequency between agents, and its effect on the mechanism of hierarchical structure formation was investigated. Like an ant, this chemotactic agent makes stochastic decisions regarding its direction of movement depending on the intensity of its released chemicals. Because of this mechanism, the agent depends on its past location history. It can perform different motions from a random walk (RW) and asymmetric attractive or repulsive interactions with other agents via the diffusion of chemotactic substances. When there is an attractive interaction between these agents, they are more likely to aggregate, which increases the effective density; thus, the disparity in the agent winning ratio is more likely to form than in a conventional model with a RW. However, in the case of repulsive interactions, the agents became more distant from each other, the effective density decreased, and a disparity in the winning ratio was less likely to form. This indicates that the disparity in the winning ratio is tunable owing to the interactions between the introduced chemotactic agents.

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