Terms and Definitions

This page simply serves as a place for me to collect and organize the common terms and ideas that I come across in my reading. I’ll be updating it with additional terms and pictures  regularly. I’m not sure how I’ll organize it. For now, I’m trying to group common/associative terms together, rather than alphabetizing everything.

Affordances: The properties of a thing that help you make a mental connection about what that thing does—or should do.

Properties that demonstrate affordance, with examples:

  • Dimensionality (buttons—indicates “clickability”)
  • Color (blue underlined text typically indicates that the text is hyperlinked)
  • Shape (handles are meant to be pulled, wheels are meant to be turned)
  • Texture (ridged edges of a window indicates it can be expanded)
  • Changing the state of an object (change of an object’s appearance when it’s clicked on or rolled over)
  • “Rollover” (changing the state of the pointer as it moves over an object, such as the pointer changing from an arrow to a curser when it movers over a text input region)
  • Pliant response (the “depressed” state of a button when it’s clicked, before the mouse is released)

Manual Affordances: The instinctive understanding of how physical objects can be manipulated with our hands. Requires no written instructions (About Face)

Examples: Wheels are meant to be turned, door knobs are meant to be twisted, handles are meant to be pulled.


  • Describes the relationship between a control, the thing it affects, and the intended result (Cooper)
  • Poor mapping requires users to stop and think about the relationship, breaking flow (Cooper)
    • Example: oven knobs corresponding with burners; the light switch on the wall that operates the garbage disposal instead of the kitchen light

Design Models

Mental Model / Conceptual Model:

  • The way a user thinks a system/product works (or should work)
  • Much simpler than the implementation model
  • The user’s mental model doesn’t always match up with how a system actuallyworks
    • Example: Most people think pushing down the break pedal on a car directly causes the wheels to slow down. A person’s foot/leg does not exert enough strength or force to slow a car, but most people don’t often consider leverage, hydraulics, or friction when they are trying to stop their vehicles.
  •  A person’s own internal representation of reality, based on past experience and how we assimilate new things into our exiting knowledge (blended definition from Cooper and Hoekman)

Implementation Model / System Model

  • Based on an understanding of how something actually works, “under the hood”
  • Does not match the user’s mental model (unless the user actually created the thing)
  • In a computer, it describes the details of the way a program is implemented in code (Cooper)
  • This model is easier for programmers to build, but harder for user’s to learn/understand
    • Example: Error dialogue boxes that list a string of code for an explanation or solution, rather than offering an explanation or solution the average user can understand and act upon.

Represented Model / Designer’s Model

  • The designers representation of a programs function to the user; how the design behaves and presents itself
  •  What the user actually sees (as opposed to what he thinks he should see or what the system itself actually does)
  • The closer the represented/designer’s model comes to the user’s mental model, the easier it is for the user to understand
  •  Allows the user to avoid learning the implantation model or how the system actually functions internally

 User-Centered Design

  • Approach to design that aims to help designers better understand the needs and wishes of users so that interactive systems can better help them meet those goals (Hoekman)
  • Puts the users at the focus of the design
  • Hoekman views user-centered design as too narrow—to focused on individual stations


  • Detailed, composite user archetypes that represent distinct groupings of behaviors, attitudes, aptitudes, goals, and motivations. (Cooper)
  • Help the designers better understand the motivations and behaviors of their user groups
  •  Important part of user-centered design

 Idiomatic Design

  • Idioms: “a group of words established by usage as having a meaning not deducible from those of the individual words” (Oxford American Dictionary); Example: Raining cats and dogs, beating around the bush, kick the bucket
  • “Idiomatic user interfaces focus not on technical knowledge or intuition of function, but rather on the learning of simple, non-metaphorical visual and behavior idioms to accomplish goals or tasks” (Human Computer Interaction 2011 Blog)
  • Based on learning how to accomplish things – a natural, human process.  (Cooper)
  • Users do not make direct parallels to “real world” ideas or functions, but focus on learning how to accomplish tasks
  •  Examples: Radio buttons, drop-down menus, close ‘x’ buttons

Metaphoric Design

  • Users rely on connections of the appearance/function of an interface to “real world” ideas or functions
  • Users make mental connections between the metaphoric design to things they have already known
  •  Example: The “Desktop”
  •  Problems:
    • The metaphors eventually break down—the either cannot display every single feature/function of it’s real world-model; or, it runs out of connections and does something the real-world model cannot do
    • Metaphors also rely on associations perceived in similar ways by both the designer and the user. If the user doesn’t have the same cultural background as the designer, it is easy for metaphors to fail (Cooper)

 Activity Centered Design

  • Focuses on understanding the activities the users are performing more than focusing on the individual users
  • Hoekman views Activity-Centered Design as too broad; doesn’t look at the user enough.

Situation Design

  • Idea refereced by Hoekman who states that designers shouldn’t focus on the person or the activity, but the situation: “It isn’t a type of person who uses an application, it’s a person in a type of situation.”
  • User’s commonalities aren’t in their behaviors or preferences (User-Centered Design), but on the fact that they are in similar situations, trying to perform similar tasks.

Self Design

  • Designing an application using yourself or your team as the “user” reference point
  • Basing the application on your needs
  • Would work well if you are designing for people like you—not so well if your clients/users don’t perform your same job/tasks

2 thoughts on “Terms and Definitions

  1. Please spell “knob” correctly. I’ll check back to see if you make the correction.

    Someone who likes correct spelling

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