# Self-learning virtual organisms in a physics simulator: on the optimal resolution of their visual system, the architecture of the nervous system and the computational complexity of the problem

## TL;DR

This paper explores how virtual organisms with different visual systems learn to navigate in a 3D environment, finding an optimal balance between visual resolution and learning efficiency.

## Contribution

The study introduces a hierarchical control architecture and identifies optimal visual system resolutions for efficient reinforcement learning in virtual organisms.

## Key findings

- An optimal range of visual resolutions balances computational complexity and task success in virtual organisms.
- Excessive sensory input or action space dimensionality slows down reinforcement learning.
- Hierarchical control modules improve locomotion and navigation efficiency in simulated environments.

## Abstract

Vision plays a key role in the lives of various organisms, enabling spatial orientation, foraging, predator avoidance and social interaction. In species with relatively simple visual systems, such as insects, effective behavioral strategies are achieved through high neural specialization, adaptation to specific environmental conditions, and the use of additional sensory systems such as olfaction or hearing. Animals with more complex vision and nervous systems, such as mammals, have greater cognitive abilities and flexibility, but this comes with increased demands on the brain’s energy costs and computational resources. Modeling the features of such systems in a virtual environment could allow researchers to explore the fundamental principles of sensorimotor integration and the limits of cognitive complexity, as well as test hypotheses about the interaction between perception, memory and decision-making mechanisms. In this work, we implement and investigate a model of virtual organisms with a visual system operating in a three-dimensional physical environment using the Unity ML-Agents software – one of the most high-performance simulation platforms currently available. We propose a hierarchical control architecture that separates locomotion and navigation tasks between two modules: (1) visual perception and decision-making, and (2) coordinated control of limb movement for locomotion in the physical environment. A series of numerical experiments was conducted to examine the influence of visual system parameters (e. g, resolution of the “first-person” view), environmental configuration and agent architectural features on the efficiency and outcomes of reinforcement learning (using the PPO algorithm). The results demonstrate the existence of an optimal range of resolutions that provide a trade-off between computational complexity and success in accomplishing the task, while excessive dimensionality of sensory inputs or action space leads to slower learning. We performed system performance profiling and identified key bottlenecks in large-scale simulations. The discussion considers biological parallels, highlighting cases of high behavioral efficiency in insects with relatively low-resolution visual systems, and the potential of neuroevolutionary approaches for adapting agent architectures. The proposed approach and the results obtained are of potential interest to researchers working on biologically inspired artificial agents, evolutionary modeling, and the study of cognitive processes in artificial systems.