Two concepts that help explain the original article are Diffusion of Innovations and Social Proof.

Diffusion of Innovations is a widely cited theory explaining why people do or don't adopt any kind of innovation, from boiling water to eating limes on British ships to installing telephones. The concept of innovators, early adopters, and late adopters comes from this theory. More relevant to this post is that this theory posits five factors contributing to adoption, one of which is Observability: you can easily see other people gaining benefit from an innovation. The more Observable an innovation, the more likely it is to be adopted. https://en.wikipedia.org/wiki/Diffusion_of_innovations

The other is Social Proof. Seeing what other people are doing, especially those that are similar to you in some way, can help steer your behavior, often in subtle and unconscious ways. There are studies about how simple signs like "people who stayed in this hotel room re-used their towels" or "most of your neighbors are reducing their electricity usage too" can shift people's behaviors, even without people explicitly realizing it. https://en.wikipedia.org/wiki/Social_proof

My colleagues and I used these concepts in several pieces of research on what we called Social Cybersecurity (joking that the term "Social Security" was already taken). The insight we had was that cybersecurity has very low observability, making it hard for innovations to diffuse through one's social network. That is, I don't know what your cybersecurity practices are, and vice versa, making it hard for best practices to be adopted.

One intervention we did was a large-scale intervention on Facebook to improve observability, showing that simple messages like "108 of your friends use extra security settings" did increase clickthru and adoption rates of those settings. https://dl.acm.org/doi/10.1145/2660267.2660271

We also have many other studies along similar lines, e.g. many triggers for talking about and adopting security are social in nature (https://www.usenix.org/system/files/conference/soups2014/sou...), that security settings that are more social in nature are more likely to be adopted (https://dl.acm.org/doi/10.1145/2675133.2675225), and more.

For solar panels, many people might be interested but also concerned how they look. When another neighbor gets them, people will get used to how they look, realize it’s not so bad, then be more likely to get them.

I don’t think the final conclusion necessarily follows, not with this example. Solar panels are big and obvious on top of the house. It’s not the same thing as other types of values spreading through a community. The house of a healthy person isn’t any different than that of an unhealthy one.

It could be simply that the door to door solar panel salesperson was covering that 1 km area.

Hmm, this actually could have policy implications. If one wants to subsidize a new technology and allocated a limited budget often the first movers are getting it and those first movers may be clusters which is not ideal driving broad adoption. So creating very small geo buckets for adoption oriented subsidies would make sense.

Kind of reminds me of "nucleation sites" in physics.

I think one factor that's missing from the explanation is the extensive media and political coverage that solar panels got: There are probably very few people by now that don't know what a roof solar panel is or who don't have an opinion on them.

So my guess is that most of those neighbors who "suddenly" decided to also get a panel, were already interested or at least curious about getting one. (In the sense of "I should totally be getting one some time, but I have no time/now idea how to start/other things are more important/etc")

Maybe the early adopter was then what changed peoples' stance from a vague idea to a concrete plan.

How about an alternative explanation?

What if a substantial amount of local solar contractors are doing door to door sales? Or other locality/proximity based sales (signs, driving a car with ads on it, and the like?)

> People who prioritize their health are more likely to have friends who prioritize their health. And so on. > > We become like the people we choose to be around.

I'm not convinced that that's it. It's more likely that the first person who got solar installed talked to their neighbors about it, and the neighbors were convinced. It's not like after you move to a neighborhood, you're really choosing anything after that point about your neighbors.

Whether solar is economically reasonable is a matter of the variables of your location. You need strong retail power parity laws, for example. If solar makes sense for one person it makes sense for the other people in the area. Why does there have to be a “catching on” effect?

A short and sweet message in this little learning of the day post. You tend to learn from your geographic neighbors. It makes sense! Can we see the same thing for ebikes, and low water lawns?

Some of it may also be neighborhoods where solar contractors went door to door selling the systems. Even if you don't buy from that salesman you get the numbers in your head and start to realize it isn't some exotic tech for elite weirdos.

a/k/a "Keeping up with the Joneses"

Somewhat analogously the best predictor of if I read a book on a given day is if I read the day before, I'd guess.

This reminds me to get solar.

Proximity is not just geographical.