Learning Paradigms · Fast-moving · Advanced
Reinforcement Learning
Also known as: RL
Learning a policy by acting in an environment and adjusting behaviour based on reward signals rather than labelled answers.
What Reinforcement Learning is
Reinforcement learning frames a problem as an agent, states, actions and rewards. The agent must discover which sequences of actions lead to long-term reward, balancing exploration of new strategies with exploitation of what already works.
How it works
Value-based methods estimate the expected return of state-action pairs; policy-gradient methods adjust the action distribution directly. Training runs millions of episodes in simulation, and reward shaping is usually the hardest part of the engineering.
Why it matters
RL underpins game-playing breakthroughs, robotic control and — through RLHF — the alignment step that turns a raw language model into a usable assistant.
Common uses
- →Robotic manipulation and locomotion
- →Data-centre cooling and energy optimisation
- →Recommendation with long-term engagement objectives
- →Preference tuning of language models
Strengths
- ✓Optimises for long-term outcomes
- ✓Learns behaviours nobody demonstrated
Watch for
- ✓Sample-inefficient
- ✓Reward misspecification produces surprising behaviour
- ✓Hard to guarantee safety
Continue exploring
More in this collection
Browse all AI ConceptsSources & References
Sutton & Barto — Reinforcement Learning: An Introduction