Using distance as our friend
Using my intensity (what I am doing) as a means to gauge how Matilda feels and whether she can respond to you marking all non reactivity. This would include not looking at me , looking at me , or looking at me and looking back to you
If you chose to use this operant approach (expecting a behavior looking /looking away) you should have a distance at which she is able to respond to the marker. Look for the latency between marking and her ability to look back at you this is important information.