The answer is: blank slate.
The term is mostly used in philosophical terms and most often has been translated into English as “blank slate” The philosophical idea behind this term (which can be traced back to Aristotle, but that is mostly known through the work of empiricist, John Lock) is that the mind is born without any information or categories inscribed in it, so that it is only through experience (in Lock, sense experience particularly) that the mind acquires a given content and rules to process this content.