Tetras are social fish and keeping them in small numbers can cause stress, which leads to ill health and abnormal behaviour. This can manifest in different ways for different individuals. They can get aggressive, or hide away, or not eat etc.
Ive never noticed tetras having any interaction due to my presence. They don't even associate me with food the same as bigger fish with larger brains do. What you see could be them trying to find something to interact with due to a lack of social interaction with others of their own species.
The magic number for tetras often seems to be cited as 6 for them to be comfortable. 6 is better than 4, 8 is better than 6 etc IMO