t is the interplay, and shifting dominance,
between the two types of feedback
relationships that give social and physical systems their dynamic character. The
many interesting dynamics that arise out of these systems are shaped by this
interplay. To catch a glimpse of the possibilities, let's combine our two previous
examples. As the diagram shown below indicates, we now have Self Confidence
setting Target Level of Performance and Target Level of Effort. How confident you
feel thus is determining both how well you think you should be able to perform as
well as how much effort you will put out in order to achieve that level of performance.
Level of Performance feeds back to determine Self Confidence. and, Level of Effort
feeds back to determine Level of Performance.
What would happen if we were to allow
this set of relationships to operate? The
answer is: it depends! It depends on the initial levels of confidence, performance
and effort (relative to each other). It also depends on the strength of the
relationships between Self Confidence and the two targets.
For example, if a decline in Self Confidence
causes a larger decline in the target
for effort than it does for performance, then the system is doomed to spiral
downward in an ever-accelerating crescendo. However, if a dip in Self Confidence
has only a nominal effect on the Target Level of Effort, the negative feedback loop
which ties Level of Performance back to change in effort will have a chance to
operate. This loop will act to boost the Level of Effort, which, in turn, will increase
the Level of Performance. An increase in performance then will inspire a rise in the
level of Self Confidence.
There are a lot of "ifs" in
these scenarios. The "ifs" depend on the relative strengths
of the feedback relationships that are involved. This simple model should begin to
give you a feel for why it is so difficult to make accurate predictions about the
performance of systems involving extensive webs of feedback relationships.
As the preceding discussion hopefully
has made clear, learning to recognize
positive and negative feedback relationships is an important skill to develop if you
are interested in gaining an understanding of a system's dynamics. The skill is
likewise extremely valuable for building expertise in the construction of system
models.
