Until the young child has learned to see beyond themselves and has the ability to see things through someone else's eyes, it is difficult to change self-centered behaviors. Most children will be 7 and older before they can begin to talk about the consequences of and plan for their own behavior. A big part of self-evaluation is social comparison. Social comparison is the act of learning from role models, imitating them, and using appropriate behaviors in a variety of settings. Time-out can be very effective when used sparingly and appropriately.
Time alone gives the child a chance to calm down.
Then the child may rejoin the activity. Children who view time out as a punishment may not use the time out situation as the caregiver intends. Use time-outs sparingly. When a time-out is used, do so because the child needs it and not because you are angry. Also, be sure the length of time is appropriate and is made clear to the child.