Suppose
you are planning a long hike and overnight stay, say to a destination that is
about 15 kilometers away. A friend has advised you not to take more than you
need in your backpack and to try to keep the weight under 20 kilograms, as that
is probably a manageable load. You pack what you think you will need and weigh
the backpack. This is tricky because your only scale is designed to weigh a
person standing on it, but the backpack keeps falling off and resting partly on
the floor. How will you weigh the backpack and determine if the load exceeds 20
kilograms? [This question is designed for any third graders who happen to be
reading these notes.]
Okay,
you determine that the load is just about 20 kilograms. Good packing, you tell
yourself. You then lift the backpack and put it on your back. It feels quite
heavy. You wonder if you can walk 15 kilometers carrying such a load. You tell
yourself that your friend is younger and stronger than you – such a load may be
manageable for her but not for you. Perhaps 10 kilos is a better target.
I
started with this story about the load in a backpack to point out a few things
about cognitive load. First, John Sweller is an outstanding scholar and has
made many important contributions to educational psychology and instructional
design, including his analysis of cognitive load in terms of intrinsic load
(that which is inherent in a problem or situation), extraneous load (that which may be eliminated from the
problem or situation and can distract some learners), and germane load (that
which is likely to help a learner focus and be successful in solving a problem
or resolving a situation). At least that is my rough and ready interpretation
of components of cognitive load theory.
Now,
I want to compare cognitive load with the load of the backpack in the initial
example. First, the backpack could be weighed so there was an independent and
relatively non-subjective measure of the load. Are there independent and
non-subjective measures of cognitive load? Could there be such measures? In any
case, in spite of the actual weight of the backpack, the perceived weight or
perceived load can vary. For my friend who is younger and physically fit, the
perceived weight of 20 kilos is moderate and manageable. For me – an older
person in not such good physical condition, the 20 kilo backpack seemed quite
heavy and not manageable. Perceived load is not the same as actual load when it
comes to backpacks.
Then,
when I think about someone trying to solve a complex problem or resolve a
challenging situation, the perceived load can also vary significantly. A highly
experienced person in solving similar problems may find the problem easily
manageable whereas someone with much less experience may fine the same problem
quite challenging. Moreover, what might be distracting in terms of extraneous
load for an inexperienced person may not be distracting for an experienced
person. Likewise, what may be germane to successful problem solving for an
experienced person may be too sketchy or too incomplete to help a much less
experienced person. So, It seems that cognitive load and the constituent parts
of cognitive load vary or can vary from one person to another; what matters is
perceived cognitive load.
Given
the usual way of eliciting perceived cognitive load on a likert scale, it seems
useful to collect other indicators, such as the time a person spends on a
particular task or which part of the task is the focus of attention or what
kind of assistance a person seeks or the level or neuronal activity or a galvanic
skin measure and so on. Having multiple measures that converge can help one
develop confidence in a reported level of perceived cognitive load. Perhaps.
Then,
because I am so prone to distraction, I wonder if there are non-cognitive
indicators that might also be relevant to cognitive load such as moods,
attitudes, and so on. Just as it is a person carrying the backpack that matters,
it is a person trying to solve a problem or resolve a situation that matters –
a person, not a disembodied mind. That reminds me … it is almost time for
lunch. Taking a break …
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