The graph below which plots the diffusion of new technologies throughout the twentieth century came to my attention via Derek Thompson’s post at The Atlantic, “The 100 Year March of Technology in One Graph.”

Take a second and click to enlarge the graph. The lines trace the percentage of US households that adopted the technologies in question over time. There’s a lot of information condensed into this chart, and of course, there’s a lot that a chart can’t convey. Below the graph I’ll list a few of the things that caught my attention.

The first thing to note is that this chart gives us a glimpse at the social history of technology, a dimension of the story of technology that sometimes gets left out. Very often the focus is on the inventors and the process of invention or on the capabilities of a technology and its consequences. But behind each of these lines there is often a very interesting, and very human story. Naturally, this chart doesn’t quite give us those stories, but they do hint at them. (Many of these stories have been told in quite compelling fashion. America Calling by Claude Fischer, for instance, is a well regarded treatment of the social history of the telephone up to 1940.)

This particular chart, however, gives the impression that technologies always track toward almost full saturation of a society. Once invented, they inexorably trend upwards, some more quickly than others. But remember what this particular chart leaves out: the myriad of technologies that fail to achieve widespread adoption and those that are superseded and recede downward toward near extinction. So consider that this chart might also have included cassette players, laser discs, and typewriters.

That said, the far end of the chart does begin to show us a little of this kind of falling off. You’ll notice, for example, that the VCR adoption rate begins to tail off around the year 2000. So too does the telephone. This is not too surprising and we can readily guess at the causes: the appearance of the DVD player and cell phone respectively. Interestingly, the computer also shows a falling off which raises the question of how the “computer” is defined for the purposes of this chart.

As an aside, this reminds us that visual data, of which we are lately so fond, tends to present itself in rather objective, even clinical fashion, but interpretations are already built in to the data.

There are also instances of dips in adoption rates on the way to full saturation. Notably we see dips in the adoption of telephones, electricity, and automobiles. Not surprisingly, the most pronounced of these dips occurred in the early 1930s as the nation entered the Great Depression. This reminds us that economic conditions play an important role in the stories of technology adoption. It also prompts certain questions: why, for example, did telephone adoption dip while radio adoption continued to increase steadily?

The point of the chart — judging by its title, “Consumption Spreads Faster Today” — is to show that technologies are adopted more quickly today than in the past. There seems to be something to this claim; in fact, it feels intuitively commonsensical to us. But at second glance, it seems a bit more complicated than that.

Remember, for starters, the problem of interpretation that is buried below the apparent objectivity of the graph. It would seem, for instance, that the Internet began in the early 1990s, but arriving at this date involves defining out of existence the early history of the Internet which stretches back into the 1970s at least. Also, several earlier technologies — the radio, the refrigerator, the color TV —  appear to rise as precipitously in adoption rate as more recent technologies.

Interesting as well are the rather languid adoption rates for certain “time-saving” household technologies such as the  clothes washer (but not the clothes dryer) and the dishwasher. By contrast, the microwave enjoys a rather steep rate of adoption. This recalls Ruth Schwartz Cowan’s classic work in the social history of technology, More Work for Mother: The Ironies of Household Technology from the Open Hearth to the Microwave, in which she dismantled the assumption that the introduction of modern household technologies radically unburdened the average housewife.

This chart, then, is chiefly valuable for what it points to: the fascinating social history of technology. It’s a history that is often forgotten, but one whose consequences we all share in. In America Calling, Fischer sums up:

“Inventors, investors, competitors, organized customers, agencies of government, the media, and others conflict over how an innovation will develop. The outcome is a particular definition and a structure for the new technology, perhaps even a “reinvention” of the device. The story could always have been otherwise if the struggles had proceeded differently.”