This is an incoherent claim, we'll see why in a second.
I ran across this quote in the latest article on linguistic relativism, What's in a name? The words behind thought by David Robson, which surveys a variety of experimental results showing top-down processes where language has some effect on mental behaviors. The article chooses not to balance this with experimental evidence showing bottom-up processing effects, but yes, there are those too.
It's a typical lightweight article that only gives you snippets on one side of a complex issue and tries to make complex things look so obvious and easy only a dummy would think otherwise. It's Fox News for linguists. It's designed to make readers say, "well, of course, that's obvious" without critically engaging in the truly interesting complexities of cognitive processes. So, back to Boroditsky's claim (I've mentioned her so much recently, I can now type her name correctly on the first try almost every time). Let me ask a simple question:
- In what way could it be possible that anything less than 100% of our total verbal experience is in our head?
Give me an example of just one verbal experience that is NOT in our head (I will accept getting hit over the head with a dictionary, if only for pure slapstick value). Also, calling "70 per cent of our total verbal experience" an average requires a funky meaning of "our total verbal experience."