The red light smack-dab in the middle of E.T.'s chest is a glowing example of empathy (no pun intended—okay, maybe a little bit). It represents understanding and shared feelings.
When we first see E.T., he's in the forest with his extra-terrestrial posse. They're spread out and studying plants. Suddenly, all of their heart lights glow, and they know it's time to jet. (You've probably experienced the same level of wordless communication with your own friends.)
When Keys shows up and pulls the plug on the plant-collecting, E.T. races back toward their spaceship with his heart light literally lighting the way. And when their ship flies away without him, the light goes out. The heart light is a symbol of their connection.
When does E.T.'s chest next light up? Not until he finally makes contact with his people again, toward the very end of the film. He's stowed away in a freezer, seemingly dead, when his heart light glows warm red, in stark contrast to the sterile hospital surroundings. "Does this mean they're coming?" Elliott excitedly asks his resurrected friend. "Yes," E.T. replies, before launching into a giddy repetition of "E.T. phone home" that threatens to tip Keys off to the fact that he's very much alive.
The final time that E.T.'s heart light shines is when he says goodbye to Elliott. E.T. points at it, and tells Elliott, "Ouch" before they embrace. Ouch is right! He's about to leave Elliott, his best friend on Earth, with whom he physically and psychically shares feelings, just as he does with his own tribe.
Now, we're not saying that when you look up "empathy" in a dictionary, you'll see a picture of E.T. and Elliott, but if that's not an example of empathy we don't know what is. E.T.'s heart light sits prominently in the middle of his chest, just as empathy and friendship sit at the center of E.T.