What I'd like to talk about in this post is drifting, because I've seen a number of discussions about how angry people were that Jaeger Pilots weren't able to magically read each-other's minds and immediately know everything about each-other.
What do I think drifting is?
In my opinion, drifting is connecting on a deeply intimate level with your co-pilot to find similar experiences or emotions that bring the two individuals together as one stronger whole.
For instance, when Yancy tells Raleigh that "I'm in your brain, I know" this statement is more indicative of their close relationship as brothers than reading Raleigh's mind. Yancy does know what Raleigh is thinking, because he knows how Raleigh thinks not because he can read his brother's mind.
One of the strongest complaints about drifting in the film is why Raleigh wasn't instantly aware of the chain sword when he and Mako first drifted. Personally, my Brother's remarks on the topic are my favorite, that it was stupid/lazy for a pilot to know that their machine had been modified and NOT find out about all of those changes immediately.
Travis Beacham, the writer for Pacific Rim, posted the following picture to visually illustrate the drift and said,
"For your reference. A half-assed verbal illustration of what a drift with a new partner might be like. Red for one mind. Blue for the other. Purple for blended thoughts. Enjoy."
(click on the picture to go to the original post)
Looking at this discussion, one can clearly see that these are two individuals that are processing different input and thinking about different things and yet, are still able to come together in order to move forward towards their common goal.
There are a number of other indications that the drift is not mind-reading. Travis says that the drift is fluid and is driven by emotions, fantasies, memories, etc. The id of one pilot cues the other pilot's id and so on and so forth (1). Raleigh did not know about the chain sword because it wasn't something that Mako thought about, even subconsciously, until the moment that she needed it. As individuals, they were thinking about different (arguably, more important) things up to that point (3).
Travis also stated that drifting can be difficult if the pilots do not share common memories to use as reference points. This can make or break a pilot team, because two minds are learning how to communicate in this entirely foreign way with another mind (2). Pilots need there to be common ground in order for their two minds to come together and successfully drift.
To sum things up, drifting is an open communication between two minds, a dialogue if you will. It does not mean that a pilot immediately knows everything about their partner. The more times a pair drifts and the longer/deeper the drift, then the more they will learn about each other.
If you'd like to read my review of the Pacific Rim Novelization, you can find that post HERE.
(1) Travis Beacham, what-memories-do-you-share-when-you-first-drift
(2) Travis Beacham, why-do-jaeger-pilots-talk-out-loud-to-their
(3) Travis Beacham, coelasquid-hey-i-actually-finished-a-comic-on-a