So for fic purposes, I’ve been toying with an alternate explanation of how the Drift and Drift Compatibility works in the Pacific Rim universe. This may or may not be canonical, I’d be curious to hear from people who know better than me.

For TOWOID, I used the Drift basically as a spirit journey vehicle which is WILDLY non-canonical and plays very fast and loose with how the Drift works in the film for story purposes. But the Kidnapping AU is shaping up to be a techno-thriller (plus fluff and lots of feels) so I wanted to have a slightly more technology-based explanation, stripped of romanticism. 

– In this theory, the act of Drifting creates an up-to-date carbon copy of the entire brain of your Drift partner in your head. 

– This basically creates a “plug” or outlet for the connection to slide home into when your brains connect when you Drift. 

– “Drift Compatibility” as a percentage is how similar your brains are before you Drift. Imagine a Venn Diagram. The more overlap between the two circles, the higher the compatibility. If your brains work on a similar model, wavelength, and structure, it means their brain can overlap with yours with the minimal amount of disruption. Basically your brain can serve as a battery that keeps the patterns of the partner’s brain functioning as usual, fully realized as a copy in your head.

– However, if one had only 50% compatibility, then the remaining 50% of the partner’s brain would likely overload what your brain and body can handle because they don’t sync. Hence: aneurisms, shock, and body failure. If you survive the process, your body has to quickly “dump” the excess, like when your computer dumps the cache memory when it gets overloaded. You might still have echoes in your brain of that person, but it would be fragmentary because you could never sustain the whole copy of their brain.

– This is another reason why two brains plugging into a third one can handle the “neural load” better. Even if they lack compatibility, they both have more “extra space” available to handle and power the incompatible parts without dying as their brain needs to rapidly offload the incompatible brain data. Hence: Newt and Hermann surviving the Drift with a Kaiju. 

– If you have 90% compatibility with your partner it means you have a pretty smooth ride when it comes to handling the copy of their brain in your brain because the sync is so high. This is also why Drifting has nothing to do with liking someone. See: Chuck and Herc Hansen. As family members, the way they think, the way they move, their memories, and their way of seeing the world probably overlaps a great deal. Liking each other has nothing to do with it, it just means Herc and Chuck can easily hold a copy of the other in their brain without disrupting their own brain.

– My theory continues that the copy in your brain becomes outdated after a while though. The Drift connection is not live, unless you are actively Drifting,  because humans do not actually have telepathy. Also, the Drift copy in your head will decay and go out of date the longer you go between Drifts, because it doesn’t have new information. So, for example, Hermann’s copy of Newt in his head is from 2025 because it was never updated. 

But, in the immediate days after a Drift, with an up-to-date copy in your head and while in the same room with your partner, experiencing the same situation and stimuli, it can get very uncannily similar to telepathy because the model of your partner in your brain will supply you with how they’re certainly going to react in that moment. “Can you believe this guy?” your partner-brain-copy says at the same moment your partner says “Can you believe this guy?” because it’s up-to-date and listening to the same guy talk.

– This also means that Newt is not in live connection with the Precursors. Rather, they need to have him Drift with them regularly with Alice to keep their orders and information in his head up to date. They’ve worked out a way to make the copy in his brain carry out orders, and may have even adjusted his brain to better sustain their model. This seems easily plausible for them, as they’re massively skilled bioengineers if they created the Kaiju. But they don’t have a live connection, they couldn’t because again, humans are not telepathic. So, except while he’s Drifting with Alice, they have no live connection so they need to plant a model in his head that will carry him through the days he’s not connected, like a computer virus that calls home for orders but is only sporadically connected to the internet. In practice, however, the difference between a live connection and the offline copy in Newt’s head would be indistinguishable unless it began to break down over days where he doesn’t connect to Alice and those orders become out of date.
This would also, tragically, explain Hermann’s certainty that Newt is a good man.