Knowledge in the head and knowledge in the world
Knowledge in the head and knowledge in the world
the powerful constraints of
more rhyming, less whining
poems are re-created as opposed to memorized
reassembling a mechanical device
: we turn screws clock- wise to tighten, counterclockwise to loosen; wood screws and machine screws look different and are inserted into different kinds of materials; etc.
= mappings where the relationship between the controls and the object to be controlled (e.g. the burners) is obvious.
Three levels of mapping
(arranged in decreasing effectiveness as memory aids)
Best mapping: Controls are 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.
Good natural mapping
: relationship of controls to burner is completely contained in world; load on human memory is much reduced.
: burden is placed upon memory, leading to more mental effort and a higher chance of error.
Mapping = good example of power of combining knowledge in world with in head
: good mapping is of special importance!
(e.g. remotely piloted airplane, building crane ...)
and design: Natural mappings can very with culture
Precise Behavior from Imprecise Knowledge
Precise behavior can emerge from imprecise knowledge because:
Great precision is not required.
Natural constraints exist in the world.
Knowledge is both in the head and in the world.
Knowledge of cultural constraints and conventions exists in the head.
Because behavior can be guided by the combination of internal and external knowledge and constraints,
the amount of material they must
, as well as the completeness, precision, accuracy, or depth of the learning.
It is actually quite amazing how often it is possible to hide one’s ignorance, to get by without understanding or even much interest.
Although it is best when people have considerable knowledge and experience using a particular
(knowledge in the head), the designer can put sufficient cues into the
(knowledge in the world) that good performance results even in the absence of previous knowledge. Combine the two, knowledge in the head and in the world, and performance is even better.
Knowledge is in the world
Functioning through 2 kinds of knowledge
= the knowledge of facts and rules
e.g. “Stop at red traffic lights.”, “New York City is north of Rome.”
Watch out: People may know many things, but that doesn’t mean they're true.
= declarative knowledge
easy to write and to teach
= procedural knowledge
= the knowledge that enables a person to be a skilled musician, to return a serve in tennis ...
difficult or impossible to write down and difficult to teach
best taught by demonstration and best learned through practice
largely subconscious, residing at the behavioral level of processing
Signifiers, physical constraints, and natural mappings
→ perceivable cues that act as knowledge in the world.
is unexpectedly required
Memory in multiple heads, multiple devices
Transactive memory & cybermind
External knowledge is often erroneous . . . It doesn’t matter where our knowledge comes from. What matters is the quality of the end result.
Technology does not make us smarter. People do not make technology smart. It is the combination of the two, the person plus the artifact, that is smart.
The partnership of technology and people makes us smarter, stronger, and better able to live in the modern world. We have become reliant on the technology and we can no longer function without it.
Not all of the knowledge required for precise behavior needs 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.
The tradeoff between knowledge in the world and in the head
Between Knowledge in the World and in the Head:
Knowledge in the World:
Information is readily and easily available whenever perceivable.
Interpretation substitutes for learning. How easy it is to interpret knowledge in the world depends upon the skill of the designer.
Slowed by the need to find and interpret the knowledge.
Ease of use at first encounter is high.
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.
Knowledge in the Head:
Material in working memory is readily available. Otherwise considerable search and effort may be required.
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.
Can be efficient, especially if so well-learned that it is automated.
Ease of use at first encounter is low.
Nothing needs to be visible, which gives more freedom to the designer. This leads to cleaner, more pleasing appearance—at the cost of ease of use at first encounter, learning, and remembering.
Knowledge in the world and knowledge in the head are both essential in our daily functioning. But to some extent we can choose to lean more heavily on one or the other. That choice requires a tradeoff; gaining the advantages of knowledge in the world means losing the advantages of knowledge in the head