Why does Malcolm choose to “conk” his hair?

Malcolm conks his hair because it's the thing to do. Everyone he admired had a conk, and it was only a matter of time.

The sharp-dressed young "cats" who hung on the comers and in the poolrooms, bars and restaurants, and who obviously didn't work
anywhere, completely entranced me. I couldn't get over marveling at how their hair was straight and shiny like white men's hair; Ella told me this was called a "conk."