Reciprocity failure is another matter entirely

“Like all spiritual realities which are the result, not of external constraint but of autonomous development, reciprocity has two aspects: reciprocity as a fact, and reciprocity as an ideal, as something which ought to be. The child begins by simply practising reciprocity, in itself not so easy a thing as one might think. Then, once he has grown accustomed to this form of equilibrium in his actions, his behaviour is altered from within, its form reacting, as it were, upon its content. What is regarded as just is no longer merely reciprocal action, but primarily behaviour that admits of indefinitely sustained reciprocity. The motto ‘Do as you would be done by’, thus comes to replace the conception of crude equality.” – Jean Piaget, The Moral Judgment of the Child (trans. Marjorie Gabain)