The 7 Cs of Interface Design

by March 1, 2004

Reeves and Nash have pointed out that people interact with media (especially interactive media) as if they were people. Accordingly, when thinking about how to design interactions between humans and computers, one must first understand the way these interactions occur between humans. Successful interface design then, is based on a through understanding of how humans interact. In particular, how individuals communicate, accomplish tasks, form relationships and make sense of their surroundings.

Interface design can be explained in terms that underscore how people communicate, collaborate, comprehend, and create. In particular, how visual and functional considerations can aid in making interactive systems more “human”. This includes concepts such as: the use of visual organization principles to create and support mental models of systems, visually communicating personalities for emotive response, and building relationships through consistency and adaptation.


Perhaps the most meaningful and commonplace form of interaction between humans is communication. Communication not only occurs through the use of words, but through the use of motion, space, and time. Likewise, interactive systems communicate in many ways. The overall visual presentation of an interface says many things about its use and origins. The timing of events in a system can indicate difficulties or guide users through a sequence. Visual organization can provide understanding and make relationships between elements and functions clear. In interface design we use these types of dialogues to communicate with our audience. Effective communication is directly responsible for user comprehension of interactive systems.

  • Four types of communication: Conversation, Instruction, Inquiry, and Debate
  • What else communicates? Time, Space, Images, and Culture


The goal of all communication is comprehension. We can talk all day long, but if nobody understands what we are saying, the effort is futile. By examining the conventions (language, personal space, facial expressions, timing, etc.) that allow us to understand the messages others send us, we can develop conventions that allow our designs to communicate effectively. By applying functional and visual principles we can provide understanding for our audience.

  • Cognitive models: Natural mappings and Metaphors
  • Indication: Visibility, Affordances, Constraints, and Motion
  • Instruction: Interaction cues/visual clues, Visual hierarchy, and Visual groupings


Comprehension can only be achieved through the clarity of our messages. (Speaking under your nose in a crowded room is not likely to get the attention of someone far away.) By using information design principles to effectively present information, we can get our message across to our audience. The goal of communication is comprehension, and comprehension can only be achieved with clarity (clear and well structured messages).

  • Appropriateness: Audience
  • Information design: Visual contrast, Least amount necessary, Separation, and Proximity
  • Inquiry: Specific vs. General


Communication can flow naturally when we are comfortable. This not only includes being comfortable in our surroundings, but also comfortable with the tone, pacing, and value of our interactions. We feel comfortable when things are familiar to us, or when we comprehend the intent and nature of our interactions. When interacting with people or objects, we form relationships with them. The more we interact the stronger and more comfortable those relationships become. We feel a connection to people when we feel that they understand us. They know how we like to do things and more importantly why. In interface design, comfort can be achieved in several ways: emotive presentation of information, recognition and personalization, adaptation, and usability.

  • Emotive response: Meeting expectations
  • Affective design principles: Color perceptions, Cultural perceptions, Sensorial correlations
  • Acceptance: Developing trust
  • Consistency
  • Usability: Ease of Learning
  • Efficiency
  • Personalization: Deliberate and Unconscious


Fundamentally, interactive systems consist of collaboration between the user and the system to achieve a goal. In order for man and machine to work together they have to speak the same language. This usually amounts to a computer trying its best to accommodate the things that make us human. This includes accommodating the differences between people with multiple interface options, encouraging participation, giving meaningful feedback at the appropriate times, and exploring unique interaction models.

  • Multiple options
  • Translations: Perception
  • Participation
  • Mutual understandings
  • Feedback: WYSIWYG and Response
  • Unique interaction models


The final goal of collaboration is creation. Everything within an interactive system is designed to support the ability to accomplish something. In order to provide the proper environment for creation, we need to understand the process individuals go through when they create. This requires an understanding of the intentions of our audience, providing a means of actualizing those intentions, and including a method to assess their actions. An interactive system is truly successful when it allows its users to create on their own terms.

  • Intent
  • Action: Direct Manipulation and Control
  • Assessment: Reaction, Change, and Analysis
  • Storming, Forming, & Norming
  • Innovation: Unique uses

Cartography (Navigation)

Anytime we are engaged in a process, we need to have an understanding of where within that process we currently are. In daily life these may be spatial, visual, or time based clues. It is no different within interactive systems. Interface elements, which orient users need to meet audience expectations by being designed with the audience’s objectives in mind. The primary responsibility of these elements is to provide users with a situational awareness. Navigation elements provide an understanding of where you are, where you have been, and where you can go.

  • Objectives
  • Expectations
  • Sequence: State Changes
  • Awareness: Spatial, Required Information, Required Controls, and Macro and micro readings
  • Small multiples