App Design & HCI Flashcards
What is HCI?
- Human-computer interaction considers the man-machine interface
- humans: single/multiple users with diverse abilities, acting competitively or cooperatively
- computers: different computing devices
- interaction: through commands and manipulating virtual objects via speech, gesture or touch
How can interactions with machines be improved?
- Explicit interaction eHCI
- implicit interaction iHCI
Why do we need HCI when designing programs?
- because poorly designed user interfaces lead to problems?
What problems can poorly designed user interfaces lead to?
- higher training costs
- higher usage costs (undermines user, high error rates)
- lower adoption (less people will use the program)
Why might people still use your interface despite it being difficult to use?
If the function of your application is important/valuable to them
What does a good design of a program do considering humans make a lot of errors?
A good design limits errors and (where possible) makes them recoverable
What 3 features must an interface be? to be successful and mean people will buy it?
useful - achieves desired user task
useable - does task easily, safely, naturally, with low error rates
used - enriches the users experience
What does the success of a product depend on?
how useable the product is
- if it brings value to the user’s life
Why was Apple’s IPod a success
It was easy to use and had a good clean design and allowed users to do something they couldn’t do before/gave them new functionality to use.
Why is it typically good to put the most important functionality right upfront for the user to see and hide away or tuck the extra functionality into a folder
so the user is not overloaded with information.
What do we need to make sure we do with dangerous features/buttons?
need to make sure dangerous buttons are placed in accessible or separate places so they won’t be accidentally pressed
What does Heckel’s law state and Heckel’s inverse law state?
- whilst usability of interface is important, the utility of the device ultimately drives user adoption
What 3 features does apple state applications should have?
- Responsiveness: system should respond to an action in a reasonable amount of time
- Permissiveness: users should reasonably be allowed to do what they want
- consistency: mechanisms should be used in the same across applications
Why do systems have to have almost immediate responsiveness?
if the system doesn’t immediately respond to their action they’ll assume they did something wrong or the device didn’t pick up their action
How does HCI improve interaction between users and computers?
- by making the devices more usable
- by making the devices receptive to the users needs
What is implicit HCI?
When the system responds to the user when the user’s act was not aimed at the system
- For example Siri thinking that you spoke to it when you weren’t addressing siri.
What is Explicit HCI?
- the user directly interacting at set points during the devices normal operation
What does it mean that humans have trichromacy
they can see 3 channels of colour RGB
What percentage of people are colour blind?
8% men and 0.5 women have red-green colorblindness.
Why is it important not to design systems based on colour?
we can’t only design systems based on colour because some people CANNOT see colour so this is not accessible.
- so never use colour alone to indicate something on an interace
- use colour to enhance an interface but consider those whose colour vision is incomplete
What does Apple’s HI page suggest apps do:
- help people focus on primary tasks and content (by limiting number of onscreen controls) (make secondary details and actions discoverable with minimal interaction)
- adapt seamlessly to appearance changes (rotate screen, features move to accommodate this)
- enable interactions that support ergonomics (controls are easier to reach in the middle or bottom area)
- with permission integrate information into app to enhance their experience without reasking for data entry
How does apple deal with when apps need to request information/check important info?
- can handle by presenting a modal view
- users must deal with this before continuing
- a safe way to exit must be provided
- must be used sparingly
Describe hierarchical navigation
- make one choice per screen until you reach intended destination
- to go to another destination, retrace steps or start from beginning and make different choices (settings)
- navigation bar
Describe flat navigation
- switch between multiple content categories
- (music application or app store)
- tab bar
