Fluid… So Fluid, with Lots of Comma Splices, It's Stream-of-Consciousness, You Know
Don't try this at home, kids. If you used comma splices as frequently and liberally as this narrator, you'd have some serious trouble in English class. But don't think Atwood doesn't know her mechanics; rather, she breaks the rules to create a stream-of-consciousness style. The narrative's style reflects the movements of the mind, where thoughts aren't always logical and sequential and don't fit easily into little boxes (or onto either side of a semicolon). Just as thoughts sometimes appear unexpectedly, popping up after an unrelated thought or intruding within a totally separate train of thought, so they pour out in a bit of a jumble in the narrator's narration.
Take, for example, the narrator's thoughts about the first time she met Joe: "Perhaps that was what he liked about me, there must have been something though I can't reconstruct our first meeting, now I can: it was in a store, I was buying some new brushes and a spray tin of fixative" (3.17). This moment gives us her whole thought process as it develops—she goes straight from saying she can't remember something to remembering it, and the use of a comma (rather than a semicolon or a period, which are more "final") highlights the fluidity of that thought process. Neat, no?