Commitment, belief and positive attitude are all important if you're going to be a success, whether you're in sports, in business or, as in my case, anthropology.
When the first fossils began to be found in eastern Africa, in the late 1950s, I thought, what a wonderful marriage this was, biology and anthropology. I was around 16 years old when I made this particular choice of academic pursuit.
Most achievers I know are people who have made a strong and deep dedication to pursuing a particular goal. That dedication took a tremendous amount of effort.
Evolution explains our biological evolution, but human beings are very unique creatures. As the Dobzhansky said, all animals are unique; humans are the uniquest. And that uniqueness of being human, language, art, culture, our dependency on culture for survival, comes from the combination of traditional biological evolution.
Journalists often ask me when I go to the field, 'What do you expect to find?' And my answer always is, 'The unexpected,' because we're just looking at the tip of the iceberg; we've just scratched the surface.
There have been some friendships lost over this. That's the most difficult for me. I find it very uncomfortable to know that I was at one time close friends with someone, and because of jealousies and misunderstandings and so on, these friendships have dissolved.
Regardless of what we look like on the outside, genetically, on the inside, everyone is an African.
One has to take initiative in life to achieve what he or she wants.
What makes us human depends on what place on our evolutionary path we're talking about. If you go back six million years ago, what makes us human is that we were walking upright. That's all. If you go to 2.6 million years ago, it's the fact that we're designing and making stone tools.
The right question to ask from a Darwinian prospective is what was it about bipedalism that was so advantageous? Why did it lead to a - why did that adaptation ultimately lead to a species Homo sapiens that has come to dominate the planet today with six and a half billion people?
I don't think we interbred with the Neanderthals at all. There are some people who think that there was some level of interbreeding. I think that we look so biologically different, that we looked and we acted so different, and we culturally were so different that we would not have had interbreeding between two species.
It's very hard for all of us, when we've committed ourselves to a particular interpretation, to change our minds.
But it really wasn't until three to four years later, when we had an opportunity in the lab to make very detailed observations, and comparisons with other fossil discoveries, that we realized she was a new species of human ancestor.
We are placed in the genus of Homo, which is Latin for man - Homo sapiens: supposedly wise men. I sometimes think - wonder - whether we really are wise men.
This was the most important discovery I had ever made in my life. It was a discovery which has irrevocably changed my whole life's direction. It immediately elevated me to the status of one of the world's leading anthropologists.
I was aware of it, but I grew up in a very a-religious family. My mother never went to church, she never had any religious training or background. It was never a part of our social interaction.