How early in life are Leadership attributes developed? This article is very interesting in investigating how leadership skills are learned.

I agree with the article you provided. I do think kid-play and interaction provides a great and valuable source of interpersonal skills - like communication and empathy. I think these are key to leadership, assuming you define leadership (at least in part) as influencing other people to achieve a goal. As the literature indicates, there are a multitude of definitions for leadership. Some even say its not very well defined, but you know it when you see it.

I think the other attribute one gets from the playground or early family life is a positive or negative outlook on life - optimism or pessimism. I think this plays a key role in leadership later on. Just my humble opinion.

I would rephrase the question from 'are' to 'can be.'

I would say, from a very early age. Leadership behaviors can be identified in very young grade school kids. They can start being cultivated in the cub scouts, little league sports, etc. I had some papers from a 4th grade teacher that talked about my leadership behaviors during the old "air raid drills" and such.

It will NOT happen with home-schooled kids or with kids who spend all their time at a keyboard.

Leadership is a cumulative learned process. I learned a lot from sports like trying your best, being fearless, and don't quit. Much to the dismay of my parents, I thought I knew everything. When I went to college I became humble as I was surrounded by kids just as smart or smarter than me. It was an era of inflection: what was my purpose in life, how to make the world a better place, and burying negative character traits.

By the time I was a 2LT I knew something about leadership and not that much more, however I think it was a stable foundation to leadership. Treat troops like I wanted to be treated as a soldier and a person. I was capable of incorporating Troop Leading Procedures and OPORDS.

By the time I was CPT, I was confident in directing my vision downward. Studs will not be abused, mentorship schemes were created, all soldiers and NCOs are given a chance to grow professionally and personally, all leaders kept the welfare of the soldiers in mind, and we will have fun as unit. I have always had the mindset that leaders care about the troops, but do not know how to show it. One needs to find innovative ways to thank them, and they will respond superbly.