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To Err is Human Computational Limits to Human Thinking : Implications for the Design of Human Centered Interfaces. Raj Reddy Carnegie Mellon University Pittsburgh, PA 15213 March 16, 2000 www.rr.cs.cmu.edu. Human Strengths and Human Limitations. Strengths: People
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To Err is HumanComputational Limits to Human Thinking : Implications for the Design of Human Centered Interfaces Raj Reddy Carnegie Mellon University Pittsburgh, PA 15213 March 16, 2000 www.rr.cs.cmu.edu
Human Strengths and Human Limitations • Strengths: People • communicate using speech and natural language • tolerate errorful, ambiguous and imprecise input • exploit vast amounts of knowledge • learn from the environment • Limitations: People • make errors • tend to forget • become impatient • get confused • need to collaborate • tend to be lazy
WIMPy Interfaces have largely Ignored Human Strengths and Human Limitations • Need to move towards SILKy Interfaces: Speech, Image, Language and Knowledge based human centered interfaces • Video of Carnegie Mellon Communicator illustrating interactive spoken language dialog
To Err is Human • Problem: • Catastrophic loss of data: “I didn’t mean to do that ” • Unanticipated side-effects: “how did that happen??” • Causes: • Sensory, Cognitive and Motor overload • Information Overload: “Like being in a traffic jam” • Timing Errors: Simplify the task • Present Solutions: • Partial Undo • Dialog Boxes
To Err is Human (Cont.) • Future Opportunities: • Unlimited Undo • Anytime Anywhere Abort • DWIM (Do What I Mean) • System Issues: • Require redesign at the OS level, network level and the application level
To Forget is Human • Problem: • A non-expert occasional user can’t be expected to remember the details • Causes: • Forgetting is the loss of indexing structure • Redundancy in the indexing structure is the key • Present Solutions: • Recognition vs. recall: GUIs and Menus • On-line manuals
To Forget is Human (Cont.) • Future Opportunities: • Use of color, fonts, voice responses for focusing attention • Intelligent Help • “How do I” and “What if” MultiMedia documentation • Learning by Doing and Learning by Example • “Reference librarian” agent • Chemical abstracts metaphor • System Issues: • On-line help must change: enormous investment
To be Impatient is Human • Problem: • Time to get the answer in interactive problem solving • Reduce the response time • Network operations: Unpredictable retrieval and browsing times • Automatic MSN and AOL updates at login • Present Solutions: • Hour glasses and wheels • No idea how long it will take • Progress bars
To be Impatient is Human (Cont.) • Future Opportunities: • Updates in the background • Learn from experience: self-aware systems • Look ahead retrieval and computation • Hurry-up algorithms • Keystroke model • Systems issues: • Introduction of monitors in OS and applications • Background multitasking: intermixed packets
To be Confused is Human • Problem: • Unable to deal with information clutter • Causes: • Information overload • Computational constraints on human thinking • Incomplete and ambiguous information • Present Solutions: • Hide and/or re-arrange windows • Illegal syntax • Restrict use of Natural Language
To be Confused is Human (Cont.) • Future Opportunities: • Infoglut: Filters and Agents • Human Attention: Use multiple sensory modalities • Incomplete and Ambiguous Information: clarification dialog • System Issues: • Agent architecture and integration into Operating Systems.
To Collaborate is Human • Problem: • Many tasks which cannot be done by a single person • Causes: • A single person may not have the skills to solve a given problem • Independent / Loosely Coupled / Closely Coupled Interactions • Present Solutions: • Instant Messaging and Chat Rooms • Serial sequential problem solving • Groupware
To Collaborate is Human (Cont.) • Future Opportunities: • Concurrent Engineering • Parallel Asynchronous Problem Solving • Common Language and Conventions • Building a bridge or plane • Distributed in Space • Distributed in Time and Space • Systems Issues: • Systems need new representations and architectures • Collaborative Writing: Transaction Files • Collaborative Design: Structured Dialog Trees • Collaborative Planning: Abstraction of Interactive Dialogs
To be Lazy is Human • Problem: • Most people use a minimal subset of functionality in Word, PowerPoint, etc. • Most people avoid tasks requiring too much cognitive effort • PGP - too much work • FTP - too complex • Causes: • Principle of least effort • Present Solutions: • Tip of the Day in Word
To be Lazy is Human (Cont.) • Future opportunities: • Advice giving agents that look over your shoulder • Just-in-time learning • Gentle slope systems • Agents (wizards!) that know about PGP, FTP, or whatever • Systems issues: • Applications that know about their own functionality • End user agent creation technology • Intelligent tutoring tools