Fundamentals and Practice Week 1

• Is a cross-disciplinary area (e.g., engineering, psychology, ergonomics, design) that deals with the theory, design, implementation, and evaluation of the ways that humans use and interact with computing devices.

  Human-Computer Interaction (HCI)
• Interaction is a concept to be distinguished from another similar term, interface.
• Interaction refers to an abstract model by which humans interact with the computing device for a given task.
• Interface is a choice of technical realization (hardware or software) of such a given interaction model.
• The letter I in HCI refers to both interaction and interface, encompassing the abstract model and the technological methodology.
• Means that the resulting interfaces are easy to use, efficient for the task, ensure safety, and lead to a correct completion of the task.

  High Usability
• Usable and efficient interaction with the computing device in turn translates to higher productivity.
• • Coined by Hansen in 1971
  • This principle simply states that the interaction and interface should cater to the needs and capabilities of the target user of the system in design.

  Know Thy User
• Task refers to the job to be accomplished by the user through the use of the interactive system. 


  Understand the Task
• • Designing interaction with as little memory load as possible is a principle that also has a theoretical basis.
  • Keeping the user’s short-term memory load light is of particular importance with regard to the interface’s role as a quick and easy guidance to the completion of the task.

  Reduce Memory Load
• The capacity of the human’s short-term memory (STM) is about 5–9 chunks of information (or items meaningful with respect to the task), famously known as the “magic number”.
• In the longer term, one way to unburden the memory load is to keep consistency. This applies to (a) both within an application and across different applications and (b) both the interaction model and interface implementation.

  Strive for Consistency
• Research shows that our brain internally rehearses information encoding during multitasking. Even a single task may proceed in different contextual spans.

  Remind Users and Refresh Their Memory
• The interaction and interface should be designed to avoid confusion and mental overload.

  Prevent Errors/Reversal of Action
• One effective technique is to present or solicit only the relevant information/action as required at a given time.
• • One might consider this rotation technique to be metaphoric because it abstracts the interaction object into the shape of a sphere, the most rotational object we know.
  • A better approach is to model interaction “metaphorically” to the real life counterpart, extracting the conceptual and abstract essence of the task. 


  Naturalness
• Naturalness refers to a trait that is reflective of various operations in our everyday life.
• A natural or metaphoric interface will also have affordance, a property that appeals to our innate perception and cognition, thus making it so intuitive that the interface would require almost no learning.
• Designing interactive products to support people and their everyday and working lives

  Interaction Design
• Principles of HCI

  • Know thy user
  • Understand the task
  • Reduce Memory Load
  • Strive for Consistency
  • Remind Users and Refresh Their Memory
  • Prevent Errors/Reversal of Action
  • Naturalness