An Iceberg

This week in class we discussed an iceberg and how it relates to the human mind. When we see an iceberg floating in the water we can only see 10% of the iceberg. The other 90% of the iceberg is hidden underwater. However, we can see a small portion of the iceberg although it is underwater. About 15% of what the water is hiding is viewable if we look up close.
How does this relate to our minds? The part of the iceberg which is completely visible is called our conscious according to Freud. The part which is underwater, but still visible upon closer examination is our pre-conscious. The part which we cannot at all see is our unconscious. Our conscious is what is known to us and our unconscious mind is what is unknown to us. The pre-conscious is what can be accessed, but it is still difficult to access.
Artists are special in that they are able to access the unconscious unlike a normal person who can only access the unconscious through dreams. Why can only an artists do that? Can anyone who studies art do access the unconscious or do they have to be born with the ability to do so?