Design of Everyday Things Excerpt - Chapter 3 Knowledge in head and in world

Knowledge in the Head and in the World

Not all knowledge required for precise behavior has to be in the head. It can be distributed — partly in the head, partly in the world, and partly in the constraints of the world.

Precise behavior can emerge from imprecise knowledge for four reasons:

1. Knowledge is both in the head and in the world. Behaviour is determined by combining the knowledge in the head with that in the world.
2. Great precision is not required. Perfect behaviour results if the combined knowledge in the head and in the world is sufficient to distinguish an appropriate choice from all others.
3. Natural constraints exist in the world. Each object has physical features that limits its relationship with other objects, the operations that can be performed on it, and so on.
4. Knowledge of cultural constraints and convention exists in the head.

Because behavior can be guided by the combination of internal and external knowledge and constraints, people can minimize the amount of material they must learn, as well as the completeness, precision, accuracy, or depth of the learning. They also can deliberately organize the environment to support behavior.

Knowledge is in the world

1. Knowledge of (Declarative Knowledge) — Knowledge of facts and rules. (Stop at red traffic lights. etc)

1. 2. Knowledge how (Procedural knowledge) — Knowledge that enables a person to be a skilled musician, to return a serve in tennis etc.

• Difficult to teach, best taught by demonstration and best learned through practice.
• Largely subconscious, residing at the behavioural level of processing.

Knowledge in the world is usually easy to come by. Signifiers, physical constraints, and natural mappings are all perceivable cues that act as knowledge in the world.

Constraints Simplify Memory (p.85) - we do make use of strong constraints that serve to simplify what must be retained in memory. For example, constraints of rhyming in poets as formulas to help memory.

Memory Is Knowledge in the Head

The Structure of Memory

Short term memory (STM)

• Retains the most recent experiences that is current being thought about.
• Information is retained automatically and retrieved without effort.
• Amount of information can be retained is limited.
• Retention is affected by both time and the number of items.
• Computer systems often enhance people’s frustration when things go wrong by presenting critical information in a message that then disappears from the display.
• To maximise efficiency of working memory it is best to present different information over different modalities: sight, sound, touch (haptics), hearing, spatial, location and gestures.

Long term memory (LTM)

• Memory for the past.
• It takes time for information to get in LTM and time and effort to get it out again.
• We do not remember our experiences as an exact recording; rather, as bits and pieces that are reconstructed and interpreted each time we recover the memories, which means they are subject to all the distortions and changes that the human explanatory mechanism, imposes upon life.
• Reconstruction of the knowledge — subject to biases and distortion.

Provide meaningful structures, which tremendously simplify the memory task. Perhaps a better way is to make memory unnecessary: put the required information in the world.

Memory in the Real World

When precision is required, use a calculator. That’s what machines are good for: providing great precision. For most purposes, estimates are good enough. Machines should focus on solving arithmetic problems. Approximate models work just fine. Effective memory uses all the clues available: knowledge in the world and in the head, combining world and mind.

Write down or take note enhance both memory and accuracy, putting memory in the world. Estimate is good enough. Estimate reduces memory load in brain. External knowledge is a valuable tool for remembering if it is available at the right place at the right time in the appropriate situation. WYSIWYG What you see is what you get!

Reminding: Prospective Memory (Memory for the future)

Prospective Memory — The task of remembering to do some activity at a future time. 

Memory for the future — Planning abilities, the ability to images future scenarios.

The ideal reminder must have: The Signal — Knowing that something is to be remembered. The Message — Remembering the information itself.

Combination of technology and people that creates super-powerful beings. It is the combination of the two, the person plus the artifact, that is smart. Together, with out tools, we are a powerful combination.