Fear, as a way of keeping species together

By Robin Dowling · 2 months ago

In the evolution simulation, I’ve introduced a system that models fear-driven behavior to promote grouping among motile organisms. Each organism continuously evaluates its surroundings to determine its level of fear, shaped by both its social context and environment.

Fear is reduced when nearby organisms of the same species are present—especially in larger numbers. Conversely, fear increases over time when the organism is isolated or surrounded by groups of other species. As fear increases, the organism becomes increasingly likely to return to the last known location where it encountered a group of its own kind.

This creates a soft pressure for organisms toward staying near their own kind, and away from others . Organisms that leave a large group but remain close to a few peers experience only a mild increase in fear, allowing smaller offshoots to explore independently and eventually rejoin the group. The result is emergent flocking behavior: groups form, fragment, and reassemble through fully decentralized decisions. There is no leader or controller—each organism acts based on its own. The overall movement resembles bird murmurations, where coordination emerges without any top-down mechanism.

Over time, this dynamic encourages stable group formation and adaptive movement across the landscape, driving species-level divergence and more complex ecological patterns in the simulated world.