This interview with Evelina Fedorenko of MIT is fascinating. She began her scientific career with an assumption, shared by many people, that language is somehow fundamental to cognition; that both language and cognition were both uniquely human abilities, and that each underpinned the other.
It’s a common – and fairly understandable – assumption. (She explains some of the reasons why it’s so intuitive in this article). In particular, most people have relatively strong inner speech – a sensation of a “voice inside our heads” that seems to enable us to think things through. That leads us to imagine that it’s this inner voice that is our thinking process.
But, as Federenko explains, it’s simply not true. There is likely to be some sort of underlying “language of thought” in our brains, but it’s not the same as natural language. Both humans with linguistic impairments and animals – who obviously lack language entirely – are capable of cognition. And Federenko also conducted experiments on people with no such impairments, checking with parts of the brain were active during cognition tasks:
“So you can come into the lab, and I can put you in the scanner, find your language regions by asking you to perform a short task that takes a few minutes – and then I can ask you to do some logic puzzles or sudoku or some complex working memory tasks or planning and decision-making. And then I can ask whether the regions that we know process language are working when you’re engaging in these other kinds of tasks. … We find time and again that the language regions are basically silent when people engage in these thinking activities.”
Language, then, is just one of several things that make us humans what we are:
“It’s most likely that what makes us human is not one ‘golden ticket’, as some call it. It’s not one thing that happened; it’s more likely that a whole bunch of systems got more sophisticated, taking up larger chunks of cortex and allowing for more complex thoughts and behaviors.”