Multiple
Baselines
Some
concerns of the A-B-A-B design include the effects
of maturation, timing of training, amount of
training, and other threats to internal validity.
For instance, through the A-B-A-B design, we
have no way of knowing if a little more biscuit
training would have increased the response even
greater than that of the praise.
We also dont know if other variables aside
from those measured actually caused the change in
behavior unless we spend a great amount of time and
effort controlling for these possible confounds.
A way to minimize these weaknesses is through
the technique known as multiple baselines.
Multiple
baselines approach uses a varying time schedule that
allows the researcher to determine if the
application of treatment is truly influencing the
change in behavior.
For example, we might vary the length of time
in the initial baseline determination and then apply
the treatment to determine if the change in behavior
corresponds with the introduction of treatment.
We might apply varying amounts of a specific
treatment (verbal praise verses verbal and physical
praise) to better understand not only the best
treatment but also the best amount of treatment.
Figure
4.4 uses the multiple baseline design to determine
if the timing of treatment is important.
Notice how the behavioral change took place
for each subject immediately following the
introduction of treatment.
This graph shows that the timing of treatment
is not important but also shows that change is
directly related to the treatment.
Figure 4.5 tells us a different story.
Had we only tested subject A, we might have
assumed that the treatment effected the change.
Subjects B and C however, demonstrate that
the treatment actually had no effect on the
behavioral change.
In fact, the behavior changed at the same
time for each subject regardless of when the
treatment was applied.
Without the time-lagged approach of multiple
baseline design, this phenomenon would have been
missed.
Figure
4.4: Determination of Best Training Method
Figure
4.5: Determination of Best Training Method
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