Reinforcement learning

Reinforcement learning

Reinforcement learning studies agents that improve decisions through interaction and reward. The objective is expected return over time, not simply predicting a labeled answer.

Ask the Reinforcement learning assistant 1 min read · Updated September 9, 2026

Definition

Reinforcement learning studies agents that improve decisions through interaction and reward. The objective is expected return over time, not simply predicting a labeled answer.

Intuition

An action can change both the immediate payoff and the situations the agent sees next. That delayed effect distinguishes a sequential problem from a one-step prediction.

Worked example

A robot may take a longer route now to reach a charging station before attempting a delivery.

The math

A policy maps a state to an action distribution: π(a∣s)\pi(a|s). An agent seeks to maximize expected cumulative reward.

In practice

Use RL when actions affect future opportunities and you can evaluate a reward safely. Start with a simple baseline.

Go deeper

Sources

More in Reinforcement learning

Assembled from the ReLU.chat curated knowledge base. These explanations are concise on purpose; check the sources for anything important.