Why do last borns act childish?

It is because they tend to be pampered by their parents.

last born act childish because they know there is no other baby competing with them

why last born act childish is that they panper them alot 

last born act childish because there is so much attention given to him or her in the family by everyone 

Because they are spoilt brats

Because, the whole condition do ensure they don’t really have to do much

Because all the older siblings and the parents baby them so they are a bit more spoiled than the rest. At least that is how it happened in my family, we know the baby is spoiled but we know we all spoiled him.

In my own opinion ,  they believe they have no competition and that attention and care will be channelled towards them by their older ones & even parents