We're so in sync

How does walking in synchrony with someone impact your relationship? Katie Haylor put this to Lynden Miles from the University of Western Australia...

Lynden - So the idea of synchrony is that we move at the same time with the same movements as somebody else, with their interaction partners.

Katie - So is this when say I'm walking down the street with a friend or a relative or maybe someone I don't know, I strike up a conversation and I find myself hitting the pavement with my feet actually at the same time as them?

Lynden - That's exactly right, that's what we'd call in phase synchrony and your footsteps tend to coordinate in the same way. Almost as if you're you're marching together with them. But often it's just happened spontaneously and unintentionally and you don't really even notice it's going on.

A lot of the time in particular the things we do for fun like singing and dancing and moving we'll practice really quite a lot that synchronizing our movements. And we tend to get the same sort of positive social benefits that we enjoy, the moving together with other people. We pay lots of attention to it, we get a lot of social feedback when we do the same thing as somebody else, tends to be that regardless of whether it's spontaneous or intentional we still enjoy the benefits of synchronous movement.

Katie - I remember being a kid and being stuck in the back of the car on a long car journey and noticing that when you're in a traffic jam, car indicators are sometimes in sync and sometimes out of sync. And it's really annoying when they're out of sync! But I also noticed that I used to do this with my friends. I would purposely try and be in step with them. Does that have any relevance here if we’re talking about social relationships?

Lynden - That's really funny because I had the same problem as a kid, I got quite annoyed when the indicators were out of sync with each other. That's what we'd call incidental synchrony. There's no real coupling between the car indicators, they come and go or they just kind of coincidentally synchronize. What's really important with people is that we have some sort of coupling or some sort of joining to them. Often it's just paying attention to them, seeing their movements and their movements influence ours and vice versa, our movements influence theirs. Until we come to a kind of a common movement frequency and we do the same thing at the same time.

Katie - So you've got mathematical with this relationship right? Can you tell us a bit about how that works?

Lynden - What we really do is just borrow some models from physics. They essentially say that as long as two things are moving at roughly the same frequency, so the same speed as each other, and somehow they're joined. So they’re coupled in some way. Often visually with people or we could hear their footsteps. Then the models predict that we’ll coordinate in either in phase coordination, so we're stepping at exactly the same time as the other person or an anti phase coordination so that for instance when we're stepping with our left leg, they'll be stepping with their right leg. And the models predict this across all sorts of systems, from metronome synchronizing, to fireflies flashing off and on, to people coordinating their footsteps.

Katie - So what does that have to do with our social relationships then?

Lynden - Turns out that when we synchronize in this way, because there's an infinite number of ways we could coordinate our behaviour, people tend to coordinate in exactly the same ways as predicted by the physics.

And that seems to be a sign of positive and effective social relationships. So we like each other more when we synchronize, we remember each other more, we get a wee boost in self-esteem.

Katie - And how strong is this relationship between socializing and being in step, literally?

Lynden - Well I guess there's a whole bunch of different things and different influences of how well we get along with each other. We almost always use strangers coming into the lab and we have simple synchrony exercises or ways of inducing synchrony with our participants. And even with strangers they tend to form a relatively tight and almost instant bond.

他们彼此改变他们思考的方式。They like each other more. They remember each other more. Typically we remember more about ourselves than we remember about other people, unless they are significant others. But after about a two or three minute period of in phase synchrony, we start to remember more about our interaction partners, as if we have formed a long term relationship with them. Our cognition and our social cognition changes in the same way they would when we've had a long term and substantial relationship with someone. They engage in more in-depth conversations and that sort of thing. And it's an interesting relationship because it kind of goes both ways. The more we synchronize with people, the more we like them, and the more we like people, the more we synchronize with them.

Katie - How have you discovered that the social cognition has changed? Are you sticking people in a scanner or are you asking them about it?

Lynden - So we do simple things like we give them a task whether moving synchronously or asynchronously, and over headphones we play them some words and ask them to say those words out loud. They believe that these words are just distraction words and so they are saying some words out loud, they are hearing an interaction partner saying some words out loud. And after two or three minutes of synchrony, then we stop them and we give them what we call a surprise recall test.

And after they've been synchronous, they remember just as many words that they've said as their partner said. But after an asynchronous interaction or they don't have movement involved in their interaction, they seem to remember more about themselves than the other person. This is what's called the self reference effect. It's really common effect. I remember more about myself than other people, except when those other people are significant others. And we can kind of replicate that long term relationship with a two to three minute period of synchrony.

We also remember what these people look like better. So we take a photograph of our participants and then we morph their faces, with a whole lot of other faces. So we end up seeing people who look similar to each other. And participants who have synchronized with an experimenter tend to better pick who the experimenter is out of a bunch of faces, much better than people who haven't synchronized.

Katie - Is there a breakdown of particular social relationships? I'm wondering if this might be quite a good dating technique, walking in step with people?

Lynden - I guess it should reinforce that initial liking between each other. We have a little bit of data that we haven't published yet that says friends probably don't coordinate or synchronize to the same extent to strangers. And we're wondering whether this is because we have this deep desire or need to belong and need to affiliate with people and need to have smooth social interactions. So we deploy coordination as a mechanism to overcome any social awkwardness and kind of close the gap between people, particularly on their initial meetings.

Katie - I'm really interested to know how long we've known about this because people have been using this technique for hundreds, thousands of years. Getting armies to march together and the social impact that must have. I mean that's got to have gone back centuries, right?

Lynden - That's right. I think we've been implicitly understanding that something about doing the same thing at the same time as each other, there's a really strong form of social bonding. There’s some ideas that this might have a deep evolutionary history and this is one of the first ways we were able to form groups and coalitions together by perhaps singing, or dancing, or drumming around the campfire. And as you say the military have used this for a very long time. The really interesting thing that the military still use a lot of marching drills. They don't march into battle anymore, perhaps it isn't so wise with the invention of the machine gun, and things along those lines. But military drills still involve a lot of marching in time and behaving in the same way as somebody else, and the idea there is that it provides a cohesive unit that provides you know a sense of belonging and a sense of camaraderie with your fellow people.

Katie - Can you tell us a bit about why you think this relationship occurs? What's the mechanism that you think you're getting at here?

Lynden - Probably a multilayered mechanism. I think doing the same thing at the same time has a lot of reinforcing properties. So we're sharing a common interest, we're sharing a common fate. It also means that we're paying attention to each other. Part of the way that we synchronize is by having an attentional coupling. By knowing what other people are doing, and seeing what other people are doing and this is also a sign of a good interaction or a good relationship. We pay lots of attention to the people we like and so it's mutually reinforcing in this way.

A wee bit lower in the system in the brain level, we get common patterns of brain activity when people are doing stuff. So again they’re sharing experiences, it tends to be again mutually reinforcing. There's some evidence that there's some hormonal changes, we may have endorphin release, a pleasure hormone, when we synchronize with other people. And so I think there's a lot of levels which all seem to reinforce the same idea that doing the same thing as their interaction partners provides a platform or a basis for an effective and pleasant social interaction.

Katie - So actually me skipping down the road with my friends, linking arms and trying to step at the same time as each other seems to make quite a lot of sense!

Lynden - Absolutely, I think it's one nice way of building up some enduring bonds.

Katie - This relationship, if it is quite a strong one, could this be used as an indicator of when for instance someone might be having social difficulties?

Lynden - Yeah absolutely. Some really recent work we've been doing is looking at social anxiety, so people who experience symptoms of social anxiety tend to have accompanying social difficulties. And what we've been showing is that the way people who have higher levels of social anxiety coordinate with other people has less stability. So the coordination is less good, it's less stable, it doesn't happen in quite the same way.
And we are starting to wonder whether this has a wee bit of a feedback loop. So if symptoms of social anxiety are producing less effective coordination, perhaps that then heightens the sensation or the experience of social anxiety, which again in turn lessens the quality of coordination. So we’re starting to do some work that looks at whether symptoms of mental health, whether deficits or disruptions to coordination can act as a marker or a signature of instability in mental health.

Katie - But it's not just stepping is it? We've been talking a lot about walking here but I’m just thinking, I played the cello as a kid. There must be so much about synchrony and asynchrony when you're making music together for instance.

Lynden - Absolutely and I think music gives people a common source or a common rhythm that they can you know use to both synchronize together really easily. But I think also other movements like posture and postural sway and just all of the little nonverbal behaviours and movements that we have, probably contribute to the same idea.

Similar emotional experiences, we mimic and synchronize each other's facial expressions and emotions as well, I think then feeds into the same idea that if we synchronize our behaviours then that can lead to a shared and common understanding.