Our 4 year old keeps nibbling on cardboard, paper, tissue, hair, etc. absent mindedly whilst distracted. Other times when she's not distracted, she just takes a bite, tells us and laughs because she knows we ask her not to do it so it seems like an attention thing sometimes.
She's generally a chewer and if she's watching TV or focusing on something, she's got to chew something. If there is nothing nearby then it'll be clothes, her nails or hair. The thing is, she might chew it, realise and spit it out or nibble and swallow a very small amount of whatever she's chewing. It seems more of a need to chew more than anything.
Could this be PICA or something else? For anyone with experience of this, what can be done about it?