What is the name of the concept in psychology that makes requirements hard to articulate? One of my teachers in Computer Science explained this idea about requirements:


  Product owners don't know what they want, they need a feedback loop of requirements gathering to push them to say precisely what the requirements should be. 


I know there are plenty of exceptions to this, but in my experience this has been generally true. 

He explained that it was related to an idea in psychology. 

My question is: What is the name of the concept in psychology that makes requirements hard to articulate?
I think the concept you are looking for is Tacit Knowledge (aslo known as implicit knowledge).

The main reason that users cannot articulate what they want, is that they do not have any conscious access to the knowledge they have acquired over the many years of practice. That’s why an iterative process is needed to bring the tacit knowledge on users awareness, so that they can articulate it.

Definition from wikipedia :


  Tacit knowledge (as opposed to formal, codified or explicit knowledge)
  is the kind of knowledge that is difficult to transfer to another
  person by means of writing it down or verbalizing it. For example,
  stating to someone that London is in the United Kingdom is a piece of
  explicit knowledge that can be written down, transmitted, and
  understood by a recipient. However, the ability to speak a language,
  knead dough, use algebra, or design and use complex equipment
  requires all sorts of knowledge that is not always known explicitly,
  even by expert practitioners, and which is difficult or impossible to
  explicitly transfer to other users.