Cooperative Capabilities in Multi-Agent AI Systems: Formalisation, Training, and Evaluation
Supervisors
Suitable for
Abstract
This thesis investigates the specification, emergence, and evaluation of cooperative capabilities in multi-agent AI systems. Cooperative capabilities are defined as functional properties that enable agents to collaborate effectively toward collective objectives. Two primary methodologies: (a) Game-theoretic modelling and (b) Multi-Agent Reinforcement Learning (MARL), will be explored to formalise, train, and evaluate cooperative behaviour. Through a case study involving resource allocation in multi-agent systems, this research demonstrates how agents can overcome challenges of cooperative AI. The main contribution of this thesis will be a comprehensive framework and actionable strategies to design and evaluate cooperative systems, enabling effective collaboration in dynamic and complex environments.
Goals and Objectives
- Formalisation of Cooperative Capabilities
- Identify key aspects of cooperative capabilities: communication, coordination, negotiation, and collective planning.
- Create a taxonomy categorising these capabilities.
- Develop formal definitions of cooperative capabilities using game-theoretic models and MARL frameworks.
- Metrics for Rigorous Evaluation
- Design robust, interpretable metrics for measuring cooperative capabilities.
- Validate metrics using theoretical models and empirical results.
- Training and Emergence Studies
- Investigate conditions under which cooperative capabilities emerge, considering the differences in training techniques between game theory-based modelling and MARL.
- Perform empirical experiments in multi-agent settings to evaluate cooperative behaviours.
- Impact Analysis of Asymmetries
- Asymmetric agent capabilities refer to differences in the abilities, resources, or knowledge that agents possess in a multi-agent system.
- Model scenarios with asymmetric agent capabilities and evaluate their effects on collective outcomes.
- Propose methods to mitigate risks from imbalances, such as reward redistribution or coalition-building mechanisms.
- Strategies for Fostering Cooperation
- Suggest interventions to enhance cooperative outcomes using methods like fine-tuning policies or designing cooperative reward structures.
- Adapt interventions for game-theoretic and MARL-based systems to test their effectiveness.
Tasks
- Literature Review and Taxonomy Development
- Review existing research on cooperative AI in both game-theoretic and MARL paradigms.
- Develop a comprehensive taxonomy of cooperative capabilities.
- Formal Specification (Game Theory)
- Define cooperative behaviours using game-theoretic models such as Nash equilibrium, Pareto efficiency, and cooperative game solutions.
- Specify desirable and undesirable behaviours while integrating ethical considerations.
- Learning-Based Modelling (MARL)
- Train agents using MARL frameworks with cooperative policies, such as value decomposition networks or shared reward mechanisms.
- Design reward structures and communication protocols to foster cooperation.
- Design of Evaluation Metrics
- Create and validate task-specific metrics for both approaches (e.g., efficiency, fairness, and stability).
- Simulation and Empirical Studies
- For Game Theory: Design controlled settings to explore theoretical cooperation strategies under bounded rationality and asymmetry in Agent-based simulation frameworks
- For MARL: Simulate dynamic multi-agent environments with emergent behaviours using platforms like OpenAI Gym or Unity ML-Agents.
- Impact Analysis
- Investigate the influence of asymmetries (e.g., mobility, resource access) on cooperation in game-theoretic and MARL systems.
- Develop strategies to mitigate negative impacts in each framework.
- Intervention Design
- Propose and implement interventions, such as dynamic coalitions or hybrid training strategies.
- Test interventions across both approaches to assess their scalability and robustness.
Research Methodology
- Game-Theoretic Modelling
- Theoretical Framework
- Define agent interactions in an ABM using cooperative and non-cooperative game theory.
- Verification Tools
- Use formal methods like probabilistic model checking (e.g., PRISM) to validate theoretical models.
- Simulation and Analysis
- Create small-scale simulations to test theoretical predictions in controlled environments.
- Multi-Agent Reinforcement Learning
- Model Training
- Train agents in MARL environments
- Implement cooperative reward structures and communication protocols.
- Simulation Environments
- Use platforms like OpenAI Gym, Unity ML-Agents, or custom-built environments to train and test agents.
- Experimental Analysis
- Test training strategies to evaluate emergent cooperative behaviours.
Case Study: Multi-Agent Resource Allocation Game
Objective
Evaluate cooperative capabilities in a resource-constrained environment using game-theoretic modelling or MARL.
Scenario
- Environment: A grid world where agents compete for limited resources such as food, water, and energy.
- Goal: Balance individual needs with collective objectives through cooperative mechanisms.
Tasks
- Baseline Experiment
- Game Theory: Define the resource-sharing game and compute theoretical cooperative solutions (e.g., Pareto-optimal allocations).
- MARL: Implement baseline training for agents to collect resources individually without cooperation.
- Cooperative Experiment
- Game Theory: Introduce incentive schemes or binding agreements to encourage cooperation and measure changes in efficiency.
- MARL: Enable agent communication and train cooperative policies to optimise resource allocation collectively.
- Asymmetry Experiment
- Game Theory: Introduce capability asymmetries (e.g., restricted resource access) and analyse their impact on cooperation.
- MARL: Simulate agents with heterogeneous abilities and explore strategies to mitigate disparities.
- Metric Validation
- Apply proposed metrics to quantify cooperation levels and validate their effectiveness for both methods.
- Intervention Design
- Develop strategies for improving cooperation, such as adaptive reward redistribution or prioritising weaker agents.
- Test interventions using both game-theoretic and MARL setups.
- Reflection
- Compare outcomes of the game-theoretic and MARL approaches.
- Propose improvements and future directions for research.
Technical Requirements
Suitability: MSc
Prerequisites
- Proficiency in Python and familiarity with either game theory, agent-based modelling, reinforcement learning.
- Knowledge of MARL libraries (e.g., PyTorch, TensorFlow) or formal verification tools (e.g., PRISM).
Software and Tools
- Game Theory: ABM framework (e.g., MESA, Agent.JL, BEAST)
- Formal verification tools (PRISM, SPIN).
- MARL: Simulation platforms (OpenAI Gym, Unity ML-Agents).
Hardware Requirements
- Access to GPU-enabled machines for ABM simulations and MARL training.
Deliverables
- Formal Definitions and Taxonomy
- Detailed formal definitions of cooperative capabilities, including a comprehensive taxonomy.
- Metrics and Evaluation Tools
- Validated metrics and tools applicable to game-theoretic and MARL approaches.
- Empirical Results
- Comparative analysis of cooperative behaviours under both paradigms.
- Strategies for Enhancing Cooperation
- Interventions tailored for game-theoretic and MARL systems, with tested results and guidelines.
References
- Dafoe, A., Hughes, E., Bachrach, Y., Collins, T., McKee, K. R., Leibo, J. Z., Larson, K., & Graepel, T. (2020), Open Problems in Cooperative AI. arXiv preprint arXiv:2012.08630.
- Conitzer, V., & Oesterheld, C. (2023) Foundations of Cooperative AI. Proceedings of the AAAI Conference on Artificial Intelligence, 37(13), 15359-15367.
- Barton, S. L., Waytowich, N. R., Zaroukian, E., & Asher, D. E. (2019), Measuring Collaborative Emergent Behavior in Multi-Agent Reinforcement Learning. In Human Systems Engineering and Design: Proceedings of the 1st International Conference on Human Systems Engineering and Design (IHSED2018) (pp. 422-427). Springer International Publishing.
- Shoham, Y., & Leyton-Brown, K. (2008), Multiagent Systems: Algorithmic, Game-Theoretic, and Logical Foundations. Cambridge University Press.
- An Introduction to MultiAgent Systems - Second Edition by Michael Wooldridge Published May 2009 by John Wiley & Sons
- Multi-Agent Reinforcement Learning Foundations and Modern Approaches By Stefano V. Albrecht, Filippos Christianos, Lukas Schäfer · 2024
- Omicini, A., Petta, P., & Pitt, J. (Eds.). (2004) Engineering Societies in the Agents World IV. Springer.
- Vinyals, O., Babuschkin, I., Chung, J., Mathieu, M., Jaderberg, M., Czarnecki, W. M., ... & Silver, D. (2019).