# Hierarchical Orchestra of Policies

arXiv: https://arxiv.org/abs/2411.03008 · HTML: https://mlsanity.com/paper/2411.03008/

## Key facts

- No citing papers in the map yet (data through 14 Oct 2026).
- Placed in Deep RL algorithms and representations, one of 15 directions in Deep reinforcement learning methods.
- Builds on 12 of its 19 references that are in the map.
- First posted on arXiv 5 Nov 2024.

## Placed in

- Deep reinforcement learning methods / [Deep RL algorithms and representations](https://mlsanity.com/deeprl/deep-rl-algorithms-and-representations/)

## Builds on (most cited first, 12 of 12)

- [Proximal Policy Optimization Algorithms](https://mlsanity.com/paper/1707.06347/) (2017)
- [Intriguing properties of neural networks](https://mlsanity.com/paper/1312.6199/) (2013)
- [Overcoming catastrophic forgetting in neural networks](https://mlsanity.com/paper/1612.00796/) (2016)
- [Asynchronous Methods for Deep Reinforcement Learning](https://mlsanity.com/paper/1602.01783/) (2016)
- [Progressive Neural Networks](https://mlsanity.com/paper/1606.04671/) (2016)
- [Continual Lifelong Learning with Neural Networks: A Review](https://mlsanity.com/paper/1802.07569/) (2018)
- [Continual Learning with Deep Generative Replay](https://mlsanity.com/paper/1705.08690/) (2017)
- [Experience Replay for Continual Learning](https://mlsanity.com/paper/1811.11682/) (2018)
- [Three scenarios for continual learning](https://mlsanity.com/paper/1904.07734/) (2019)
- [Progress & Compress: A scalable framework for continual learning](https://mlsanity.com/paper/1805.06370/) (2018)
- [Leveraging Procedural Generation to Benchmark Reinforcement Learning](https://mlsanity.com/paper/1912.01588/) (2019)
- [Policy Optimization via Adv2: Adversarial Learning on Advantage Functions](https://mlsanity.com/paper/2310.16473/) (2023)

## Abstract (arXiv)

Continual reinforcement learning poses a major challenge due to the tendency of agents to experience catastrophic forgetting when learning sequential tasks. In this paper, we introduce a modularity-based approach, called Hierarchical Orchestra of Policies (HOP), designed to mitigate catastrophic forgetting in lifelong reinforcement learning. HOP dynamically forms a hierarchy of policies based on a similarity metric between the current observations and previously encountered observations in successful tasks. Unlike other state-of-the-art methods, HOP does not require task labelling, allowing for robust adaptation in environments where boundaries between tasks are ambiguous. Our experiments, conducted across multiple tasks in a procedurally generated suite of environments, demonstrate that HOP significantly outperforms baseline methods in retaining knowledge across tasks and performs comparably to state-of-the-art transfer methods that require task labelling. Moreover, HOP achieves this without compromising performance when tasks remain constant, highlighting its versatility.