Any parent knows that babies are empathetic little creatures, with an innate ability to know when their mum or dad is happy or sad.
Well, this father decided to prove what we all know by conducting an experiment with his six-month-old – and the results are, well, tear-jerking.
In a clip posted on YouTube, the baby, called Aris, initially appears quite content as he sits on his dad's lap and listens along to him addressing the camera.
His dad states: "I just had to get it on video so you could see that Aris is a natural sweetheart...anytime he sees me crying it makes him want to cry too."
As he gets the experiment under way, the dad mimics the sound of a cry and immediately little Aris reacts with a look of concern while shaking his head.
As he gazes up at his dad, Aris then proceeds to cry along with him until the pair stop in unison as if nothing ever happened.
The dad, from Kaufman County, Texas, then tests the theory twice more by turning on the waterworks, and without fail Aris scrunches up his face and starts to bawl.
Aww, diddums. Make it stop now. You're upsetting us.