Do parents drill twins to be alike in every way or would it have developed that way anyhow?

What do you think about people who dress their identical twins the same like a pair of bookends? I have seen this often and it is like the twins from toddlerdom are made to choose their attire as a team and not as individuals. And a lot of twins who act as a team, two haves that make a whole, creating their own language or finishing each other’s sentences. Do they do that because they genetically are so similar or is it conditioned into them in the growing process by society and parents that kind of expect twins to be part of a whole and not two individuals. Around town there were two Hispanic ladies you never seen with a man or alone for that matter, they had to be late 20s or early 30s and you always seen them dress, and style their hair exactly alike. I wonder if it was something they chose to do or continue to do, or it was something drilled into them all their lives since they were children that they could not break?