While the main goal of foreshadowing is to keep readers turning pages, when you foreshadow you also make later plot turns and character choices believable.
Doing so makes a promise to the reader that's important to honor.
Believing What Happens Later
If you foreshadow a character's future action or a plot twist, that helps keep readers immersed in your story. Otherwise they they may pause and question what to you seems like a natural story development.
As an example, in Pride and Prejudice Elizabeth Bennet engages in a friendly debate about Bingley, the man her sister loves.
WARNING: spoilers below. But you've read Pride and Prejudice already, haven't you? No? What are you waiting for?
Bingley's friend Darcy criticizes Bingley for what he calls an “indirect boast.” (Nowadays some might call it a humble brag). Bingley admits to thinking and writing so rapidly he sometimes conveys nothing to the reader and to being likely to act on the spur of the moment.
As the three debate whether those qualities are pluses or minuses, Darcy points out that Bingley might easily change plans if asked by a friend to do so.
Darcy sees that as a fault, but Elizabeth points out that regard for one’s friend can be admirable and might often persuade a person to do something without waiting for a specific reason.
The scene contains its own conflict due to Darcy's and Elizabeth's unacknowledged feelings for each other. Also, Elizabeth wishes to forward her sister's and Bingley's romance. Bingley's sisters and Darcy oppose it.
So the scene stands alone fairly well, and the dialogue is great fun to read.
But the exchange also lays the groundwork for later conflict. Bingley, acting on the spur of the moment and under the influence of Darcy, leaves town and does not return, breaking the heart of Elizabeth's sister Jane.
Without this earlier exchange about Bingley's character and his willingness to act on a friend's request, readers would be far less likely to believe that he'd abandon Jane. Darcy's role in the Bingley/Jane drama and Elizabeth's reaction to it drive much of the novel.
Because of that, it's key that readers believe Bingley would take off at a moment's notice without giving a lot of thought to what might happen down the road.
He Did What?
The debate between Darcy and Elizabeth also gives us, ahead of time, reasons for Bingley's actions that make them more understandable.
Without that foreshadowing readers might not want Bingley and Jane to get together again. He'd seem like he purposely misled Jane or that his affections were less strong than hers and too easily changeable.
Also, Elizabeth saying early on–and when it doesn't affect her sister–that willingness to defer to friend's wishes can be a positive trait means she's all the more willing to lay Bingley's actions at Darcy's door. And it makes clear that Darcy understands how much influence he has on his friend.
Readers are more apt to believe the feelings and actions of all three characters because of what at first seemed like mere drawing room conversation to pass the time.
You've probably heard the old saying that if there's a gun on the table in Act 1, it needs to be used by the end of the play.
Readers consciously expect a gun (or a bomb under the table) to matter if it's shown to them. They'll wonder about it throughout the book and feel let down if in the end it doesn't matter.
That type of foreshadowing also makes a promise about what type of story to expect. The gun suggests violence, suspense, perhaps a thriller or mystery. If you instead hand readers a romantic comedy, they'll feel cheated and angry that they spent their time reading your book.
Similarly, if you start your novel with a meet cute and one of the characters is murdered halfway through, most readers will put down the book and never return.
This guideline applies in a more subtle way when you foreshadow the way Austen did with the Elizabeth/Darcy debate.
As I mentioned, the dialogue is fun to read all on its own. Also, there's probably enough conflict that readers wouldn't wonder why it was there even if it had nothing to do with later events.
The entire novel, however, contains many such exchanges that foreshadow later events. If none of them led to anything significant, half of Pride and Prejudice would simply be witty banter. It's doubtful people would still be reading and writing about the classic novel today if that were so.
Because all those conversations also hint at what's to come, though, each time I read the book I see something new and engaging in it. Each time I'm more impressed by how Austen wove her plot together and I'm more engaged by the characters.
That’s all for now. Until next Friday, when we'll talk about one way to make your novel a fast read—