Which AI system, created by Terry A. Winograd, enabled interactive natural-language dialogue about a simplified “blocks world” domain?

Introduction / Context:
Early natural-language understanding systems often restricted their domains to make language interpretation tractable. The “blocks world” is a simplified micro-world of geometric objects with actions like move, stack, and unstack. Terry A. Winograd’s system is famous for engaging in dialogue about this world, interpreting commands and answering questions in plain language.

Given Data / Assumptions:

• The system supported interactive dialogue.
• The domain is the simplified blocks world.
• We need the specific system’s name among classic AI programs.

Concept / Approach:
SHRDLU is Winograd’s seminal natural-language system that parsed commands, reasoned about a blocks-world state, and carried out actions in a simulated environment. It integrated parsing, semantic interpretation, discourse context, and planning, illustrating how domain restriction could yield robust NL interaction. The other listed names correspond to different systems or concepts: SIMD is a parallel architecture class, BACON is a scientific discovery program (Langley et al.), and STUDENT (Weizenbaum’s ELIZA variants and other early programs) are not Winograd’s blocks-world system.

Step-by-Step Solution:

Verification / Alternative check:
Historical AI texts and videos demonstrate SHRDLU manipulating a virtual block scene, answering questions about the scene, and executing multi-step commands, affirming the identification.

Why Other Options Are Wrong:

• SIMD: architecture category, not an NL system.
• BACON: program for scientific law discovery, not blocks world.
• STUDENT: different early AI program; not Winograd’s blocks world work.
• None of the above: incorrect because SHRDLU is correct.

Common Pitfalls:
Confusing SHRDLU with ELIZA or PARRY; mixing up program names from the same era.

Final Answer:
SHRDLU