Some of the post hoc estimates would be better specified using -gltCode instead of -glfCode, as this would provide more informative directionality in the comparisons. For example:
-glfCode DigitvLetter "category : 1*Digit -1*Letter" \
-glfCode DotsvLetter "category : 1*Dots -1*Letter" \
-glfCode DigitvDots "category : 1*Digit -1*Dots" \
could be revised as:
-gltCode DigitvLetter "category : 1*Digit -1*Letter" \
-gltCode DotsvLetter "category : 1*Dots -1*Letter" \
-gltCode DigitvDots "category : 1*Digit -1*Dots" \
Additionally, the reason the age effects did not work is due to the following lines:
-glfCode DigitvLetterNovelvAge "category : 1*Digit -1*Letter & 1*Digit -1*BACS1 age" \
-glfCode DotsvLetterNovelvAge "category : 1*Dots -1*Letter & 1*Digit -1*BACS1 age" \
-glfCode DigitvLettervAge "category : 1*Digit -1*Letter age" \
-glfCode DotsvLettervAge "category : 1*Dots -1*Letter age" \
-glfCode DigitvDotsvAge "category : 1*Digit -1*Dots age" \
which should instead be specified as:
-glfCode DigitvLetterNovelvAge "category : 1*Digit -1*Letter & 1*Digit -1*BACS1 age :" \
-glfCode DotsvLetterNovelvAge "category : 1*Dots -1*Letter & 1*Digit -1*BACS1 age :" \
-gltCode DigitvLettervAge "category : 1*Digit -1*Letter age :" \
-gltCode DotsvLettervAge "category : 1*Dots -1*Letter age :" \
-gltCode DigitvDotsvAge "category : 1*Digit -1*Dots age :" \
Also, do you think that age might influence motion? If so, directly including motion as a covariate could be problematic. For further discussion on this issue, see this blog post and the associated paper.
Gang Chen