Cognitive workload relates to the mental effort required to perform tasks.
It is a useful diagnostic of situations where users have to expend excessive
mental effort to achieve acceptable performance, and is particularly important
in safety-critical applications.
Cognitive workload is closely related to comfort: even if a system is
apparently acceptable for use, it may be low in comfort if it demands
too little or too much mental effort. A task demanding too little mental
effort may result in a lowered efficiency because it leads to boredom
and lack of vigilance, which directly lowers effectiveness. Excessive
cognitive workload may also result in lowered effectiveness, if it causes
information to be missed and results in errors. This is a particularly
important issue in situations where safety is critical, e.g. air traffic
control and process control. Measures of cognitive workload can be used
to predict these types of problems.
What is Cognition
A factor relevant to the individual perception of credibility regarding
a web site is the perceived efficiency at which the user is able to complete
certain tasks on the site. Effective operation of an interactive tool
is dependent on the ease at which the user is able to learn the interface
and anticipate the navigational schema. To figure out what methods would
lend themselves more easily to an interactively ergonomic interface, you
need to understand how the mind works, and what processes it goes through
to arrive at certain conclusions.
The breadth of research on cognitive theory is much to great to summarize
in any kind of specific detail for this site, but highlighting a couple
of aspects of the cognitive model of learning might prove useful to any
The process of learning, under the cognitive model, is predominantly an
internal process of the individual doing the learning. Most knowledge
acquisition is understood as being transmitted in a one-way process from
the "teacher" to the "learner." The information is somehow copied exactly
from one brain to another. This, however, is not altogether that accurate,
given the way the human mind works. The learner is an active processor
of information who internally constructs individualized knowledge. Increasing
the efficiency of a teaching tool (any web site with information to convey)
would require the designer of the tool to re-conceptualize the "teaching"
process from a "transmission" model to an "integration" model.
In Instructional Design: Implications from Cognitive Science, the
author indicates that new information that is to be "integrated" with
a learner must be modified to fit within existing individual knowledge
structures called "schemas." For integration to occur successfully, an
existing schema must be modified in one of three ways:
- Accretion (minor additions to existing schema),
- Tuning (minor modifications to an existing schema), or
- Restructuring (major modification of an existing schema)
In the case of interactive media, the schema in question is "interaction
methods to item(s) I learn from/with." Early web designers were at least
instinctively aware of this "Schema Modification Theory," as their designs
could be easily identified as alterations of well established metaphors.
It was not uncommon in the early days of the world wide web to see sites
that functioned almost exactly like a book, table of contents and all.
On other sites one might find pages mimicking either an audio tape player
or a VCR with images a visitor might click on to stop, go forward, or
reverse. These examples of "piggy-backing" on existing visual and organizational
metaphors serve as excellent examples of accretion, but are usually understood
as only mildly successful in terms of usability.
In hindsight, one can see that these first attempts to allow an individual
to successfully navigate and retrieve information from an "interactive"
resource were steps toward a more complete schema restructuring.
It may be premature to say that an entirely new schema has been constructed,
on a socio-cultural level that reflects the "Internet" metaphor, but it
is certainly on it's way. Television commercials and advertising have
begun to tune their own schemas by including "visual idioms" unique
to the world wide web.
It is important to realize that the Internet has begun to integrate itself
into the social consciousness in such a fashion that any effort by a web
designer to do anything but restructuring would be a step backward.
Because the web is a unique medium, it cannot be forced into a television,
radio, or library metaphor. Or rather, it can, but it will limit the capabilities
of the tool, and thus, the efficiency at which information can be gathered,
and knowledge learned.
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