mIt's possible that one of the major integration techniques with a psychological twist will be an ability to tell stories. Humans are wired for storytelling, are easily immersed in telling stories and enjoy listening to them. Storytelling may convey a point that is impossible to convey in any other way with the same effectiveness.
How does it connect with the integration? The ability to explain how the system reacts to some event is the hallmark of the Integration Engineer - one has to choose the important information from the wealth of the technical documentation, integrate the mental model and communicate it to the listeners in a simple way that hides the underlying complexityto be able to tell a compelling story.
Now - in order to be a genuine integration technique, the story has to use only available lower-level design information to describe the higher-level behavior without the right to use higher-level information and risk the tautologies.
The ability to tell the story of system's reaction to single event does not guarantee that the whole system story will be told but the trace of that specific event will be validated. Any missing information that prevents the story to flow may be tagged as a possible design anomaly to be resolved until the integrators will be able to tell the story, the whole story and nothing but the story so help them God. In this way the storytelling could be used as a design validation technique.
When the results of the tests on the hierarchy level of interest are combined with the design information on the lower level as the building blocks for the story, effective integration testing techniques may emerge.
And it's much more fun to tell and listen to stories than to read, write and execute endless test scrips so there is no harm will be done if the storytelling techniques will be added to the toolkit of the Integration Engineer.
So the First Secret of Integration may be formulated as "The Integration is the ability to tell a compelling, complete and accurate story about how the system works when used in a certain way".