Nylon straps-rear seat

[RikDavis]

I have just noticed that there are 3 nylon loops of 1 inch nylon, One behind each head rest on the rear seat. They appear to run behind the seat back. It would seem reasonable they are some kind of seat back release but I have tugged on them and nothing happens.
Anyone know what these are for and if I just need to pull harder?.
Truck is a 2013 Tradesman crew cab

 

[CBari]

They are for child safety seats

 

[RikDavis]

They are for child safety seats

Thanks, That makes sense. Not the sort of thing I think about in my 70's

 

[BarryG]

On my 01 quad cab they are on the front side of the seat back and they make a dandy holder for a 4 foot level and/or my 4 foot cb antennae when I am not using it.