Camille remembers the first time she noticed talking to herself out loud. “It was almost like, ‘Oh, that’s my voice’, in a way that I wouldn’t have thought of it if I’d been speaking in a meeting. I was usually reporting on what I was doing. I might say, ‘Go on, take an onion; take an onion and chop it up.’ I think it reminded me of certain kinds of play.” For all that the pandemic has taken from us, it may have helped us to become more aware of some aspects of our everyday mental processes, like the fact that many of us talk to ourselves, out loud as well as silently in our heads, for much of the time. Many of us will have spent more time alone in the past 16 months than ever before. In the case of my friend Camille, the awareness sprang from deep isolation: her partner was stuck in a foreign country and she was living alone with little contact apart from Zoom meetings. Her out-loud self-talk seemed partly about creating company for herself, and partly something more deeply existential, an affirmation of her own continuing being. And she noticed that she was doing it more during lockdown. “It’s being on your own in a pandemic: all of a sudden the walls close in in a different way. I felt kind of flattened by it; just the fact that it was flatlining, it was all the same.” Her words were literally breaking the silence. “It’s a kind of punctuation, isn’t it?” In other instances, people tell me they’ve found themselves doing it to guide themselves through a busy, but often lonely, day at work: one work-from-homer explained he talks himself through stressful “logjams” when he feels he has too much on – and no real-life colleagues to turn to. Language is a multifunctional device. We use it to make things happen: to ask questions, to give orders, to beg forgiveness. Whatever it can achieve out there in the social world, it can do just as well when it is only ourselves who are listening. These functions of self-talk have been a growing focus of research in recent years. Known as private speech in its out-loud form, self-talk is particularly noticeable in children speaking to themselves when playing or thinking through a task. Its silent form, inner speech, is the conversation many of us report having with ourselves when we are going about our daily business. This internal, silent version appears to develop from the out-loud form, as we internalise the exchanges we have with others into conversations with the self. Those conversations gradually become more compressed and abbreviated, so that talking to ourselves is more like a note-form version of what would otherwise be fully spelled-out sentences. Big claims have been made for the power of self-talk. Many studies have the flaw of giving people instructions to talk to themselves and then actually never measuring what kind of speech results. When scientists go to the trouble of asking people what their inner speech is like, they find great variety. Some of us appear to be doing it all the time, while others (to the recent astonishment of the internet) say they don’t do it at all. Getting good data on something so elusive and intimate is a challenge, but new methods mean that the science of inner speech thrives. One way in which the experience varies is the extent to which it takes the form of a dialogue. There is evidence that taking on the structure of a conversation might be particularly valuable for flexible, creative trains of thought. One main function of inner speech is thinking problems through in language: guiding and controlling the self just as the understanding words of a caregiver can guide a child. When the going gets tough – when we are stressed or faced with a difficult task – the highly abbreviated inner speech that probably occupies much of our waking lives can become expanded into a full-blown dialogue. It can also take on the out-loud form it had when we were children. Words that assume a material form – that hang in the air as spoken utterances – have a particular power: a point made by the philosopher Andy Clark. Combine that with social isolation (and thus the absence of the usual inhibitions that might make us keep it all to ourselves), and you end up with a perfectly natural response to lockdown. That’s because thinking in words is inherently a social process. We are constantly taking on other perspectives in our inner dialogues and responding to them: challenging, agreeing, qualifying, persuading. When we lack the usual social foils to bounce ideas off, it’s no wonder that we simply do it for ourselves. The range of individuals who can join in our internal conversations is limited only by our imaginations. It’s not uncommon for people to report other characters finding voice in their inner speech, including deceased loved ones, imaginary companions and spiritual beings. There are plenty of pros to self-talk, but cons as well. In mental health conditions such as anxiety and depression, negative comments to the self can be damaging, and something that therapy will try to get a grip on. Whether positive or negative, a greater understanding of the words in our heads and what they are doing there can only be a good thing. There is no single reason why you might have been talking to yourself more during the pandemic. Although it hasn’t yet been studied systematically, there are reasons to think that lockdown self-talk, if you have found yourself in that habit, is really just an external version of what you were probably doing internally for a lot of the time anyway. At an elemental level, it might be because it is a fun and comforting thing to do. Camille found that her flourishing self-dialogue took in other interlocutors as well. “I did talk to the odd thing, like a bird. I would ask the bird a question: ‘What are you doing? Goodness me.’” Charles Fernyhough is a writer and psychologist. He is the author of The Voices Within: The history and science of how we talk to ourselves