--- title: "Rational agent; think/act like humans" subject: "Artificial Intelligence" chapter: 1 key: "semester_6/artificial_intelligence:rational-agent-think-act-humanly" source: https://www.bctengineer.com/q/semester_6/artificial_intelligence/rational-agent-think-act-humanly site: BCT Engineering --- # Rational agent; think/act like humans Artificial Intelligence · Chapter 1: Introduction - Asked in: 2074 Bhadra, 1+6 marks - Video: [What is Artificial Intelligence? Approaches to AI:Thinking&Acting humanly|Thinking&Acting rationally](https://www.youtube.com/watch?v=xpIRp_Ylxpw) — Study with Dr. Dafda - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/artificial_intelligence/rational-agent-think-act-humanly - Whole chapter: https://www.bctengineer.com/md/semester_6/artificial_intelligence/chapter-1 ## Question What is a rational agent? "System that think like humans" and "System that act like humans" are the part of artificial intelligence. Justify these statements with practical example. ## Short answer A rational agent selects actions that maximise its performance measure based on percepts and built-in knowledge. Systems that think like humans model internal reasoning (e.g., General Problem Solver), while systems that act like humans mimic behaviour (e.g., chatbot) – both are part of AI as human-like dimensions. ## Answer #### Rational agent A **rational agent** is an agent that, for every possible percept sequence, selects the action expected to maximise its performance measure, given the evidence from the percept sequence and its built-in knowledge. Example: a robot vacuum that cleans the maximum area with minimum battery. ```text Environment --percepts--> [ Agent ] --actions--> Environment ``` #### "Systems that think like humans" (cognitive modelling) This approach tries to build programs whose *reasoning process* matches human thinking. First we must know how humans think, through introspection, psychological experiments and brain imaging. If the program's input-output behaviour and the **timing/steps** match human data, its mechanism may reflect the human mind. - It is the field of **cognitive science**. - *Example:* Newell and Simon's **General Problem Solver (GPS)** compared its reasoning steps with the thinking-aloud records of people solving the same problems. Artificial neural networks that model brain neurons and cognitive architectures like SOAR are other examples. - *Practical use:* A tutoring system that models how a student solves algebra, to find where the student goes wrong. #### "Systems that act like humans" (Turing-test approach) Here the behaviour, not the inner process, must look human. The system passes if a human cannot tell whether it is a machine (Turing Test). It requires NLP, knowledge representation, reasoning, learning (and vision and robotics for the total test). - *Example:* A customer-service chatbot or a voice assistant like Siri that understands speech and replies naturally. A humanoid robot like Sophia that talks, recognises faces and shows expressions. **Justification:** Both are parts of AI because AI covers two dimensions: *thought process vs behaviour*, and *human-like vs ideal (rational)*. Thinking humanly and acting humanly are the "human-like" side of these dimensions; thinking rationally and acting rationally are the "ideal" side. Together they make the four definitions of AI in Russell and Norvig. | | Human-like | Rational | |---|---|---| | Thinking | Think like humans (cognitive science) | Laws of thought (logic) | | Acting | Act like humans (Turing Test) | Rational agent | ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What does a rational agent do for each percept sequence? A. Chooses a random action B. Copies human behaviour C. Selects the action expected to maximise its performance measure D. Always takes the cheapest action Answer: C. A rational agent picks the action expected to maximise performance given its percepts and built-in knowledge. (Key point: Rational agent) 2. What is the focus of 'systems that think like humans'? A. Only matching outputs B. Using formal logic laws C. Maximising performance D. Making the reasoning process match human thinking (cognitive modelling) Answer: D. This approach models the human reasoning process, as in cognitive science and GPS. (Key point: Thinking humanly) 3. In 'systems that act like humans', what must look human? A. The behaviour, not the inner process B. The hardware C. The inner reasoning steps D. The programming language Answer: A. The Turing Test approach judges behaviour only. (Key point: Acting humanly) 4. Which two dimensions give the four definitions of AI? A. Speed vs memory, and cost vs size B. Thought process vs behaviour, and human-like vs rational C. Hardware vs software, and learning vs search D. Input vs output, and logic vs rules Answer: B. Crossing thinking/acting with human-like/rational gives the four views. 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