I watched a fascinating TED talk on The Neurons that Shaped Civilization by Vilayanur Ramachandran. This seven-minute presentation is about “mirror neurons”. Ramachandran shares research which shows that, when we watch others performing an action, a similar set of neurons appear to be activated in our heads as theirs.
That makes sense of how observing others can help us develop our own skills and sensibilities. Perhaps, for example, we learn so much from playing with excellent musicians not just because we listen to what they are doing but also because of subtleties like how we see them forming and sounding their notes or relaxing in difficult phrases and making them seem easy. I can see it also has a more sinister side, perhaps bearing on mob mentality, and gives us more responsibility for what we chose to watch, such as action films were the solution is always violent. The eye, indeed, is the lamp of the body! (qv. Matthew 6:22