By middle mouse clicking on a block in survival (While having the block in your inventory) it appears on your head but does not duplicate it. For a better explanation view the link under steps. I'm too lazy to write steps so I made a video instead

What I expected to happen was...:
Forgetting I wasn't in creative, I expected nothing. Upon going into a third person view I realized I was wearing the block and still had it in my inventory.

What actually happened was...:
I began to wear the block on my head.

Steps to Reproduce:
Steps are demonstrated in the video: https://youtu.be/inixKHKqMSE