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THE DESIGN OF EVERYDAY THINGS - Chap 3: KNOWLEDGE IN THE HEAD AND IN THE WORLD

THE DESIGN OF EVERYDAY THINGS

Chap 3: KNOWLEDGE IN THE HEAD AND IN THE WORLD

Precise Behavior from Imprecise Knowledge

Reasons why precise behaviour can emerge from imprecise knowledge

  1. Knowledge is both in the head and in the world
  2. Great precision is not required
  3. Natural constraints exist in the world
  4. Knowledge of cultural constraints and conventions exists in the head

Memory Is Knowledge in the Head

Make something too secure, it becomes less secure

If you have to change your password frequently, you may want to have similar password every time. It is not secure.

Because people have to memorize the password, it tends to be '1234', 'p@ssw0rd', 'qwerty', etc.

Otherwise, you may put a post-it your password is written on your laptop.

The safest common schemas requiring at least two different kinds:

  • Something you have: 2FA's code
  • Something you know: password

The Structure of Memory

There're two types of memory

  1. Short-term / working memory
  • Memory for arbitrary things
  1. Long-term memory
  • Memory for meaningful things

Approximate Models: Memory in the Real World

Conscious thinking takes time and mental resources.

Simplify thought is to reduce the resources. It's ok to memorize pi = 3.14

Knowledge in the Head

  • People write down
  • People enter it into their equipment
  • People remember some of it as meaningful phrases

It requires special skills to remember (memory in your head). Thus people use a paper to write notes (external memory = memory in the world)"

The Tradeoff Between Knowledge in the World and in the Head

Knowledge in the World Knowledge in the Head
Information is readily and easily available whenever perceivable Material in working memory is readily available. Otherwise considerable search and effort may be required.
Interpretation substitutes for learning. How easy it os to interpret knowledge in the world depends upon the skill of the designer Requires learning, which can be considerable. Learning is made easier if there is meaning or structure to the material or if there is a good conceptual model
Slowed by the need to find and interpret the knowledge Can be efficient, especially if so well-learned that it is automated
Ease of use at first encounter is high Ease of use at first encounter is low
Can be ugly and inelegant, especially if there is a need to maintain a lot of knowledge. This can lead to clutter. Here is where the skills of the graphics and industrial designer play major roles Nothing needs to be visible, which gives more freedom to the designer. his leads to cleaner, more pleasing appearance - at the cost of ease of use at first encounter, learning, and remembering

Memory in Multiple Heads, Multiple Devices

People can add idea, then constrain the choices and make it done - 'transactive memory'

People also rely on devices to memorize

Technology does not make us smarter. People do not make technology smart.

Natural Mapping

You want meaningful mapping

  • Best mapping: Controls area mounted directly on the item to be controlled
  • Second-best mapping: Controls are as close as possible to the object to be controlled
  • Third-best mapping: Controls are arranged in the same spatial configuration as the objects to be controlled

What stove do you think it's easy to use?

Culture and Design: Natural Mappings Can Vary with Culture

In some culture, people write right to left, or other

In some culture, things go bottom to top

Mac's scroll pad has changed its direction after touch panels appeared

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