CS474: Human Computer Interaction - Applications in Constrained Environments
Activity Goals
The goals of this activity are:- To identify how constraints are employed as implicit signifiers
Supplemental Reading
Feel free to visit these resources for supplemental background reading material.The Activity
Directions
Consider the activity models and answer the questions provided. First reflect on these questions on your own briefly, before discussing and comparing your thoughts with your group. Appoint one member of your group to discuss your findings with the class, and the rest of the group should help that member prepare their response. Answer each question individually from the activity, and compare with your group to prepare for our whole-class discussion. After class, think about the questions in the reflective prompt and respond to those individually in your notebook. Report out on areas of disagreement or items for which you and your group identified alternative approaches. Write down and report out questions you encountered along the way for group discussion.Model 1: Leveraging Constraints for Discovery
Questions
- What makes the assembly in Norman Figure 4.1 so easy to put together without instructions?
- What is different about the outlets of various amperages in the figure above? Are their shapes different out of functional necessity?
- Look up aviation design maneuvering speed (Va). What does this speed represent?
- Many vehicles only allow the rear-view camera to activate when the vehicle is in reverse. This is an example of an interlock. What is an interlock and why is this done?
- Imagine a scenario in which a device automatically turns off unless a certain smart phone is within proximity of the device. How might this work, what would be the benefit, and how might you indicate that the device is available or locked?
- What are other examples of environmental constraints to facilitate correct user operation?
- Can you identify examples where the addition of a constraint would improve the usability of a device?
Explore Further
These curated resources show constraints used deliberately in demanding, real-world environments:
- Nielsen Norman Group - Preventing User Errors: Avoiding Unconscious Slips — how constraints and forcing functions prevent skilled users’ slips (Norman’s Ch. 5 territory); note the examples of interlocks and confirmations that make dangerous actions physically harder.
- Apple Human Interface Guidelines - CarPlay — a design environment where the constraint is safety-critical: every element must survive the “two-second glance.” Notice how much functionality is deliberately removed relative to the phone app.
- Android for TV - Design Guidelines — the “10-foot UI” problem: a low-precision D-pad remote, a distant screen, and a relaxed user. Compare the focus-based navigation model to a touchscreen’s, and count the constraints doing signifier work.
- Interaction Design Foundation - Constraints in Design — a written overview of Norman’s physical, cultural, semantic, and logical constraint categories with everyday examples to classify.