I agree that not every child is similar in fears at age 3.
Nurture or nature that a child is fearful or a risk taker, don't know. I know in those personality/career tests, I went off the charts as a risk taker (and I end up a trader) and when my daughter was 9 months, she was sitting with a little girl 11 months. A big wave came in and wash over them. The father of the other girl, standing in the water in front of them, was just as amazed as I that the girls were unfazed by it. And now, a big wave will take wipe her out on the boogie board(all 38 lbs of her) and she will struggle up with sand in hair, nose and inside swim suit everywhere and just say she needs to take a break. When we were at Disney World, Animal Kingdom and some African dance show was going on and they had a bunch of adult women and some teens volunteering to dance with them. My 2.5YO daughter was dancing beside me in the audience. The male dancer came up to her and put out his hand, she took it and started dancing with him towards the front and center of the performance and did a little duet with him.
I do not know what I did to raise a bold child but I do know that will serve her as much as her brain will. But I do think, since she imitates a lot of what she sees DH and I do, that it is more nuture, her experiences with me.
I remember being with my father, he was buying a new car and gave the man a price. It was very low and I was embarrased as only a teenager can be with her father. It was not accepted and we left. That night, the dealer called my father and we were getting a new car at that price. I remember a few other times. Always, embarrased that my father would bargain like that. I have been to markets in Turkey and Morocco and SE Asia and I bargain like a native, thanks to my father. If they don't take my price, I walk away. Without my father, I wouldn't. So how do our children learn this. I didn't start out that way.
Ren