1966 — First chatbot
ELIZA
1966 & 2026
The very first program simulating a psychotherapist, created by Joseph Weizenbaum at MIT, and its modern reinterpretation in 2026. Compare both versions side‑by‑side with the same message and explore the internal workings of each engine.
19662026RulesLanguage model
Pedagogical comparison
Enter a message: it is sent simultaneously to both engines. Observe each pipeline, explore the internal steps and understand why the responses differ.
Why are these responses different?
ELIZA 1966
- • Hand‑written rule engine
- • No language understanding
- • No memory between messages
- • Fixed replies, chosen from a list
- • Fast, deterministic, transparent
ELIZA 2026
- • Language model (≈ 7 B parameters)
- • Contextual understanding
- • Conversation memory
- • Dynamically generated reply
- • Adapts to tone and topic
ELIZA 1966
Rule‑based engine
Waiting for a message…
ELIZA 2026
Language model
Waiting for a message…
Connecting to AI provider…

