The theory not only explains the first order effects which are dominant
in angle range of 
to 
, but also accounts for the second
order effects which can be seen in 
to 
range, where the
sign of the effects is reversed.
If one includes the second order effect, it can be considered as an
effective cross-orientation (90 degrees) interaction of range 
and
the strength of decorrelation feedback 
. For the orientation
adaptation, the Equation 11 is now
For the orientation contrast, the Equation 13 is now
The comparison of the theoretical predictions with the experimental data
is shown in Figure 6. The parameters used are 
for
both effects and 
and 
for the orientation adaptation
and orientation contrast respectively. Note that 
for both effects, and 
is much smaller than 
and thus for
second order effect.
Figure 6:
Quantitative comparison of the theoretical predictions with the
experimental data of orientation contrast (left) and orientation
adaptation (right). This figure includes second order effec.