Politicians often provide good fodder for language commentary, and one of Barack Obama's comments during the debates has been rattling around in my head for a while now. He made a comment that some people think he's "green behind the ears," and that struck me as a mixed metaphor.
What Is a Metaphor?
I'll back up. First, a metaphor is a way of comparing two unrelated things to make your point more vivid. For example, Shakespeare said, "All the world's a stage." He compared the world to a stage to make his point that we're all like actors in a play. That's a metaphor.
Another example of a well-known metaphor is to say someone is walking on thin ice. It is a way of saying someone is doing something dangerous and creates a vivid image of a person needing to behave carefully to avoid falling through an ice covered lake.
The big difference between a metaphor and a simile is that a metaphor doesn't use the word "like" and a simile does. For example, it's a metaphor to say "All the world's a stage," and it's a simile to say "All the world is like a stage." Not a big difference in meaning, but it's the kind of thing you can get tripped up on if you're in school and you have to take a test about similes and metaphors.
You can remember that similes use the word "like" because "simile" has the letter "l" in it.
What Is a Mixed Metaphor?
So back to mixed metaphors. A mixed metaphor is when someone combines two unrelated metaphors. For example, two common metaphors someone can use to tell you to get a clue are “wake up and smell the coffee,” implying you need to be more alert, and “read the writing on the wall,” implying you need to see the bad news that is already right in front of you. A radio host once told me his favorite mixed metaphor combined those two. Someone told him to “Wake up and smell the coffee on the wall.” Suddenly the imagery doesn't make so much sense. Did someone throw coffee on the wall?
Sports metaphors tend to be popular and they're also easy to mix. For example, if you tried to motivate your co-workers by saying, “It's our turn at bat, so let's make this touchdown for the company,” you'd have mixed baseball and American football metaphors, and if you try to imagine the image that goes with the metaphor, you don't know whether to put your players on a baseball field or a football field.
Can Mixed Metaphors Be Fun?
Because they usually undermine the imagery of both of the metaphors that are combined, mixed metaphors are generally considered bad form. But sometimes people also like to play with mixed metaphors. It can be a fun way to turn a cliché on its head. For example, I've seen people mix the metaphors “Let's cross that bridge when we come to it,” meaning let's put off the decision, and “Don't burn your bridges” meaning don't destroy a something you'll need later. They get “We'll burn that bridge when we come to it,” which combines the meaning of the two metaphors into something like “We're ready to fight when the right time comes,” and still maintains imagery that makes sense.
Did Obama Mix Metaphors?
So back to Obama and his “green behind the ears” statement. I immediately thought that he was mixing “wet behind the ears” with “green” -- two different metaphors that mean someone is naïve, young, or inexperienced.
The most common explanation for why “wet behind the ears” means young is that new babies are born covered in fluid, so they're wet, and behind the ears is one of the last places that dries if they aren't wiped off (1, 2).
There are a few reasons “green” can mean young and inexperienced – branches are green before they harden into brown wood, and apparently horns can also be green in young animals, thus the word “greenhorn (3, 4).”
Obama certainly wasn't the first person to utter “green behind the ears.” I found multiple examples of previous use in publications including The New York Times (5, 6), The Economist (7), and the Financial Times (8), but just because other people said it first doesn't mean it isn't a mixed metaphor.
Commentators on Ben Zimmer's column about Obama's mixed metaphor pointed out that the German equivalent of “green behind the ears” -- “grün hinter den Ohren” -- is common in Germany (9), and a Google search does show that it comes up more frequently than “green behind the ears,” so I tend to believe the commentators although I have no first-hand knowledge of the saying in German*.
Finally, I surveyed my Twitter friends, and a couple of people said that “green behind the ears” is a common metaphor used by corn farmers and refers to young ears of corn. I was unable to verify this, but Obama is from Illinois – a corn growing region – so the explanation seems plausible. So Obama may have heard this expression around his home state, although I still suspect that if farmers are using “green behind the ears” it's still just a widely adopted mix of “wet behind the ears” and “green” because the imagery of “green behind the ears” doesn't make sense to me. But I'll be the first to admit I don't know much about corn farming, so if someone out there wants to leave a comment and set me straight, I welcome the information.
So I don't feel as if I can give you a definitive answer to the question of whether Obama used a mixed metaphor, the best I can do is to say “Probably,” but I do hope I've given you a better idea of what mixed metaphors are and why it's usually best to avoid them.