He explained the term using a surreal anecdote about two men on a train, which he repeated in interviews for decades. Hitch claimed the term was a Scottish name, and he would tell the following joke to illustrate its inherent "emptiness."
Man A: "What’s that package up there in the baggage rack?"
Man B: "Oh, that’s a MacGuffin."
Man A: "What’s a MacGuffin?"
Man B: "Well, it’s an apparatus for trapping lions in the Scottish Highlands."
Man A: "But there are no lions in the Scottish Highlands!"
Man B: "Well, then that’s no MacGuffin!"
His point was that a MacGuffin is a purely mechanical element used to "trigger" the plot.
Hitchcock’s personal favorite MacGuffin was the "government secrets" in North by Northwest. He called it his best because it was the emptiest. The hero asks what the villain is selling. The agent replies: "Oh, just government secrets." By refusing to even name the secrets, he proved that the object only exists to give the characters a reason to chase each other.
An additional origin note is that while Hitchcock popularized the term, he credited its creation to his friend and screenwriter Angus MacPhail. They likely chose the name because it sounded like a common Scottish surname, adding to the "nonsense" nature of the joke. Some film historians also point out that the word "guff" is British slang for "nonsense" or "empty talk," which fits the definition perfectly.
Sometimes the MacGuffin is considered to be the same as a "red herring", but while both are plot devices used to manipulate the audience’s attention, they serve completely different structural purposes.
The MacGuffin is the motivation. It is the thing the characters are chasing. It doesn't matter what it is, as long as the characters want it badly enough to drive the story.
A non-Hitchcock example is the statue in The Maltese Falcon. Everyone is killing each other to find it, but it could have been any object that was considered valuable by the characters.
A red herring, as I have written earlier) is a clue, character, or plot point that is intentionally misleading. It’s designed to make you reach a false conclusion so that the eventual "twist" is more shocking.
In the Harry Potter book and movie series (especially in The Prisoner of Azkaban), we are led to believe that Sirius Black is a villain trying to kill Harry. Throughout much of the series, Snape is also seen as working to harm Harry, when in fact he is protecting him.
