# What is Causal Language Model? Definition & Technical Mechanics

> **Source:** [SPIDITS AI AI Glossary](https://spidits.com/ai-glossary)  
> **Category:** Natural Language Processing  
> **Canonical Citation:** [https://spidits.com/ai-glossary/causal-language-model](https://spidits.com/ai-glossary/causal-language-model)

## Definition
A Causal Language Model is an autoregressive model trained to predict the next token in a sequence given only the preceding tokens. It uses attention masking to prevent the model from looking at future tokens during training.

## Architectural Mechanics & Deep Dive
A causal language model is a type of autoregressive language model trained to predict the next token in a sequence while strictly prohibited from looking at future tokens. This is implemented using causal masking, which hides downstream text during training. Causal language models (such as the GPT series) are optimized for text generation and dialogue, as they generate coherent continuations based purely on the left-hand history.

## Industry Applications & Real-World Use Cases
Conversational agents, creative text generation, and code autocomplete systems.

## Frequently Asked Questions

### What is the difference between causal and masked language models?
Causal models predict the next token based only on left context (e.g. GPT). Masked models predict hidden tokens based on both left and right context (e.g. BERT).

### Why are causal language models preferred for chatbots?
Because they are optimized for step-by-step generative decoding, mimicking the way humans construct sentences word by word.

## Related Terminology
- [autoregressive-model](https://spidits.com/ai-glossary/autoregressive-model)
- [gpt](https://spidits.com/ai-glossary/gpt)
- [tokenization](https://spidits.com/ai-glossary/tokenization)

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*From the SPIDITS AI Knowledge Base (336+ terms indexed). Explore full technical definitions: [https://spidits.com/ai-glossary](https://spidits.com/ai-glossary)*