Hello swansnot. (Good name BTW.)
Okay, I'll try to explain as best I can what I mean. If it's okay, I'll start with our old friend the double slit experiment. Okay - and if you don't mind I'm going to stick with electrons for this example because its counterpart - the anti-electron (positron) is a different sort of thing (i.e. it has a +ve charge), whereas an anti-photon and a photon are the same thing entirely (and there are all sorts of issues with the directionality of time, that I don't properly understand,).
So, we fire an electron through the first slit. It then somehow makes its way through the two slits on the next screen and ends up at the back at a point which is consistent with a uniform pattern of interference. In other words, the electron has acted as though something has interfered with it and has deflected it accordingly. In the MWI the 'somethings' that are interfering with the electron are other (shadow) electrons, tangible only when they are following the same path of reality. They act in the same way as the electron that we can detect, and are only evident through inference after seeing how our detectable electron behaves (i.e. as though it was being deflected by other particles with the same physical properties).
My question is, does this apply to anti-electrons too (I think it probably must,) or are anti-electrons another way of explaining 'shadow' electrons, but within a different interpretation of interference phenomena?
Cheers.
P.S I hope it doesn't annoy everyone too much that I keep calling positrons 'anti-electrons'. It's just so that it's as clear as possible what I mean when comparing them to shadow electrons.
[Edited to change a 'which' to a 'with'.]