According to Lev Vygotsky, basic mental capacities are transformed into higher cognitive processes primarily through social interaction. All the other important processes i.e. association with stimulus and response, or adaptation and organization, as well as rewards and punishment, come next to social interaction. A child develops his cognitive abilities through interactions with others. He/she grows and gradually starts to communicate with others. The development theory further talks about signs, symbols, languages, written or verbal interactions, numerical systems, all of which are entirely a process leading to transformation of basic mental capabilities into complex forms. These are outlined very well in this theory.