Coming up with my favorite Chico streets in a recent post has started me thinking about what a neighborhood is.

If I'm considering only how it should look, a neighborhood must be full of surprises, with each lot different from the next. Just about everything built since the end of World War II has been mass-produced, creating an appearance that is too homogeneous to be counted as a neighborhood.

But there's another quality that makes for a neighborhood that has nothing to do with how it looks. For want of a better term, let's call it social cohesion. This dimension of neighborhood is a measure of how people who live in it act toward each other.

I first experienced a neighborhood  when I was a child living in the area that would later become known as Silicon Valley. It was a neighborhood mainly in the social sense, although location and economic status also set it apart from its surroundings.

We lived in a solid middle-class neighborhood built in the late 1940s. It was surrounded by prune orchards and rural slums. Even as a kid, I knew that the street just beyond the next orchard was full of trashy people, including wild kids who liked to bully the better-behaved kids in our neighborhood.

Our neighborhood was full of families with two to five children. Most of the mothers stayed at home. They would meet each other for coffee at their  houses. The dads were around on weekends. It was your typical baby boomer gestation zone. The adults in the neighborhood looked out for all the kids. We felt safe there. But if we were looking for a little danger and adventure, we could head to the orchards or the slums.

The houses in our neighborhood were all custom-built, but they were modest and nondescript in that 1950s way. They certainly weren't charmers. Our house had a self-consciously modern look.

When we moved to Santa Rosa when I was 12, we went from the suburbs to an older neighborhood. Again, location and economic status set us somewhat apart from our surroundings. This time we were outside the affluent part of town. My parents opted for a  less glamorous neighborhood because it allowed us to afford a huge house. There were five kids in our family and we each had our own bedroom.

Our neighborhood consisted of three one-block parallel streets connected by a single street at the end of the block. We were sandwiched between a placid creek and the busy main street of town. For no apparent reason, our street was populated by European immigrants. In our neighborhood, English was spoken with German, Austrian, Russian and Finnish accents. There weren't as many families in this neighborhood, but at least on our own street, the residents knew us and looked out for us.

The houses were built around the turn of the 20th century. Some of them had two stories. But they were by no means charmers. They were vaguely Victorian or craftsman.

As an adult, I've had few experiences of neighborhoods in a social sense. In the last 40 years people's ties have become based on shared interests rather than proximity. The shrinking number of kids in post baby boom America has made neighborhoods less socially cohesive than they used to be.

Also, neighborhoods just aren't that important to me. In a social sense, I'm the boy in the bubble. I don't make much of an effort to meet people, and I usually keep my distance from people who try to get to know me. I live in world where 6.5 billion people are strangers, 2,000 are acquaintances and 20 are close friends and family members. So the social advantages of neighborhoods mean less to me than they do to most people.

Despite my self-contained nature, I'm by no means a hermit. I have a  family after all, though I suspect my wife wouldn't have minded if I'd been more of a talker.

One of the things I've always like about writing for a newspaper is that it has forced me to go out and talk to people. I find most of these encounters to be enriching and energizing, yet I'm always happy to regain my solitude afterward. One of the things I like about being a flaneur -- a sentient ambler through urban space -- is that it forces me to have random encounters with people. One of the reasons I like San Francisco so much is that it has such a vibrant street life. By contrast, Chico's streets are pretty quiet, but there are enough people out there to make things interesting.

I almost refused a recent encounter. I was walking through the neighborhood east of downtown and passed a couple of Chico State students who were tossing a Frisbee back and forth. One of them urged me to catch it and toss it to his friend. At first I said no, but then I asked myself, "Why you are you being so uptight?"

I couldn't come up with a good answer. So I caught the Frisbee, tossed it, caught it again and tossed it one more time before continuing  my walk, feeling invigorated by my decision to step outside my bubble.

The life of a flaneur is full of opportunities to observe people, but once in a while there are invitations to interact. I'm trying to become more comfortable about accepting them.