This post is also available in Dutch.
We have already explained what happens in your brain when you pick up the phone, but a lot more happens during your conversations: you talk, your friend begins to talk and you listen, you respond, and maybe you wildly gesture around or you laugh. In a regular conversation, all of this happens incredibly quickly, but how can your brain manage all of these tasks at the same time?
The speed of sound
Your brain is doing a lot while you’re talking and listening: the areas of your brain responsible for hearing, talking and remembering are constantly hard at work. In one moment, you’re talking while your brain is looking for the correct words and gestures; in the next moment, you’re listening while your brain is working to perceive and process everything that’s being said—making it all into a coherent whole and, if possible, making sure that you look like you care about the conversation. To make matters worse for language researchers, your brain does this incredibly quickly.
In a regular conversation, there are around 200 milliseconds between you saying something and your friend’s response—even faster than the blink of an eye! What’s more, in most experiments, people take around a second to say a word. So while you’re listening, your brain must predict when it’s your turn to talk or whether your friend wants to keep talking. You also have to keep track of what’s actually being said: if your friend asks a question, you should respond differently from how you would if they were to tell a joke.
Lucky for us, our brain is a phenomenal prediction machine. To do this, we make use of a great many cues. If your friend is talking, they show signals that indicate the end of their speaking turn. They can talk with a different intonation, stretch the last syllable of words or cease to gesture. They can emphasise the end of their turn even more by using typical phrases, such as but uh, or something, you know. And if you’re not ready to talk, you can bounce back just as easily: nodding or saying mm-hmm or yeah, which often does the trick. If your friend wants to keep talking, they’ll turn their head away from you or keep gesturing.
If both of you are prepared to switch from speaker to listener and vice versa, you give the proper response. Your brain is already working on what you want to say, finding the right words to do so and preparing your muscles to talk. Finally, your brain must also produce a grammatically correct sentence! This last part is often simplified via your knowledge of the way you and your friend talk (the discourse); you talk in a certain way with your friend, and often about similar subjects. In this way, you can rapidly recognise whether you should formulate a regular sentence or respond to a question. Actually, recognising questions is even easier; for example, in many languages they are signalled at the beginning of a sentence by a particular sentence structure or the fact that your friend talks in a higher pitch. You also respond more quickly to a question when it is accompanied by gestures.
Your brain is tracking many things during a conversation. It listens to the words used and tracks pitch, intonation, gestures and eye contact. And all of these signals work in a conversation involving only two people! Things get more and more complicated when there are more people involved. It’s a good thing we’re very adept in conversing with multiple people as well (we even tend to look at the next speaker before they begin to talk). Conversations are thus not as simple as they may seem and language researchers have a lot to figure out. I guess it’s a good thing we talk so much…