People have “mental models” of how things work, built from

• affordances
• causality
• constraints
• mapping
• positive transfer
• population stereotypes/cultural standards
• instructions
• interactions
  
  

Know your Audience/Users

• Who are you designing for?
• Rule of thumb:
  • cater to 95% of audience (5th or 95th percentile)
  • but means 5% of population may be (seriously!)compromised
• designing for the average a mistake may exclude half the audience
• computers and visibility: font size, line thickness, color for color-blind people?

quotes of wisdom:

You do NOT necessarily represent a good average user of equipment or systems you design

Do not expect others to think and behave as you do, or as you might like them to.

People vary in thought and behaviour just as they do physically

Design Stages/Steps