Of course. This kind of converging brain activity is an important part of how empathy works: by inferring what another person's brain is doing and replicating that in our own brain, we feel what they feel, and this 'synchrony' lets us understand and respond to them. It's basically the closest thing we have to telepathy.
In a co-parenting situation, the activity you see is each parents' brains emulating both the child's brain and their own. That results in a higher degree of similarity than each co-parent on their own, because in that case they're only empathizing with one other person (the child).
You would see the same result in other highly emotional three-party situations; a co-parenting situation would just be a good way to trigger it.
I think it’s actually the fact that ‘roles‘ have generally been established once a couple has been together for a while, and when the couple is together in this case they are in execute-the-plan mode.
When it’s just one half of the couple, theres a realization that they have to fill both roles. The mental scavenging required to prioritize/sequence/execute a blend of familiar and unfamiliar actions is going to perturb brain activity.
It is actually other way round. I was more often without other person, so the only me situation was easier to execute and "plan". Other person presence inference sometimes requires more thinking or complications due to acting unpredictably.
Other person makes it easier in a sense that there are two hands and you can split kids. So you don't change diapers while watching other kid. But in terms of how usual situation is, how much cooperation and negotiation it requires, it requires more.
Exactly. When we're used to alternate parenting and work, and rarely do "co-parenting" simultaneously, it can happen that both us assume the other is currently watching after the child, when neither is :-\
We see this in situations involving co-workers and neighbors, friends and even strangers. There's the point-source stimulus and its first order effects we react to but it's mediated by the reactions we observe from those around us participating in the same experience resulting in second-order (and more) effects.
Isn't this effectively the psychology of crowds writ small?
In a co-parenting situation, the activity you see is each parents' brains emulating both the child's brain and their own. That results in a higher degree of similarity than each co-parent on their own, because in that case they're only empathizing with one other person (the child).
You would see the same result in other highly emotional three-party situations; a co-parenting situation would just be a good way to trigger it.