In its simplest form, it is like a submarine sending out a sonar, to which a return signal is sent. It is like your partner is saying “are you there for me?”. They might make a random comment like “that’s a big flock of seagulls”. All you really need to do is respond to show you’ve been listening - ie “it is! Did you see the big Pacific Gull in with all those Silver Gulls?”. Ignoring or not saying anything, means it was a failed bid for connection.
https://www.gottman.com/blog/an-introduction-to-emotional-bids-and-trust
https://www.youtube.com/watch?v=ib7Ain2aVR0 [2:09]
keywords - connection, bidding for connection