... but that was a very long time ago & I can’t remember what it was called. I just remember a few bits about it such as:

Baby reaches out arm and makes a grasping movement with his/her hand MEANS the baby wants to be given the object which the hand is pointing toward.

Baby leans to the side MEANS “Hello friend”.

Baby leans forward MEANS “I feel angry with you!!”

There was a lot more. I was a teenager myself when I read it & I was reading purely out of interest as I didn’t know any babies to try it out with. As a result much of it has faded from memory.

I do remember that babies will respond to the same behaviour in other people of any age (other babies, toddlers, adults, whatever). If you do the reach and grasp movement to a toddler the toddler will get the object you’re beckoning toward and give it to you.

Something else that was pointed out was this. Often when an adult says “hello” to a baby or toddler, such as a mother picking a toddler up from nursery, the adult will lean forward toward the child. This is the sign language for aggression and the toddler will sense that. It’s better to lean sideways (“Hello friend”).

I’ve watched all this in babies & toddlers when I’ve had the chance & I often see all this happening. I once saw a toddler communicating with a baby in a pram. The toddler seemed to know exactly what the baby was saying and would tell the adults what she was wanting (though I can’t vouch for the accuracy of that – could have been toddler imagination!).