Pattern name for putting "barriers" between classes

Sometimes putting a "barrier" between classes can be very helpful in the long run (although it seems a problem at the beginning). For example, in Rails models are not able to call the controller or the views. This helps having clean/testable/flexible code. Is there a name for this?

For example, when all the classes have references to other classes and are able to send messages to them, you end with code that is coupled.