Do they Know? Part II

This is the same but a little different. Whenever my Absolutely Gorgeous Wife (AGW) and I hug in our house one if not both of our kids come running and must push their way in between us. Tonight the kids were in the other room and we tested the theory as it was quiet and we thought they were up to no good so my AGW and I hugged and within about 15 seconds the Girl came running in and squeezed in. Then in another 30 seconds the Boy came and started working his way in. So how do they know?