I recently gave a talk at the Fresno County Archaeological Society's monthly meeting, and while it required a good deal of prep work and stress, I am very glad that I did it - it was a good audience, and alot of fun to give the talk.
After the formal presentation, there was a Q&A period, as is common at these types of events, and I was asked a range of questions, most of which got into the information that I had left out of the presentation (when you are giving a 1-hour talk for the lay public, you have to leave out alot of interesting and important details, unfortunately. It's a matter of making sure that the audience has enough information for your main points to make sense, while hopefully whetting their appetite to look further into the topic on their own - hopefully stoking their curiosity rather than "dumbing down" the subject matter). However, there was one question that struck me as interesting, but not for the reason that the person asking it intended.
After I had answered several questions, I called on a well-dressed, middle-aged man near the back of the room. He stood and asked "so, you say that these people were hunter-gatherers, but they had to have grown some crops, so what did they do to fertilize them?" He then rattled off a description of Native American crop fertilization that could have been taken verbatim from one of my elementary school Social Studies books. He followed this up with some additional comments about how "every society must have agriculture."
Had he stopped before giving his example of Native American agriculture, I would have assumed that he was asking a slightly different, and very interesting question. But his insistence (even after I answered his question to the best of my ability) that the Chumash (the Native Californian group about which I had been speaking) engaged in some form of agriculture, complete with the intentional fertilization of planted crops, was just the most recent example of something that I have noticed among the lay public ever since I first became interested in both history and archaeology.
Most of us have preconceptions regarding the past based in part on half-remembered snippets of our educations, in part on our conception of the present, and in part on our basic assumptions about how humans behave. This fellow was unable to accept that there are human populations who do not engage in agriculture, even after I explained the full spectrum that runs from highly mobile hunter/gatherers to farmers*. Similarly, the people that I encounter very often seem to have difficulty grasping that there are, indeed, societies that don't really recognize the concept of private property, or lack clearly defined social strata (no, not every society has a leader, at least not a permanent one). Both of these ideas (private property is a natural part of human psychology, all humans follow leaders and all human society are stratified for this reason) are based on assumptions that we make which aren't actually backed up by field data. Or, to de-nerdify the way that I phrased that, we like to think that these things are true because they either justify our current society.
Similarly, we have certain notions regarding the human past based on pop culture. The very notion of "back in caveman times" is ludicrous and informed more by Warner Brothers cartoons than archaeology. Some past humans lived in caves...but, you know, some modern humans live in caves. When you think of the "caveman days", though, you are thinking of a point when humans were anatomically modern (or at least nearly so), but somehow not quite human...primitive, savage, lacking language and culture.
This was never the case. Nobody knows for sure when language began, but it was likely before we became anatomically modern humans. Likewise, culture pre-dated modern humans - the presence of stone tools and artwork associated with our ancestors demonstrate that. By the time we evolved into our currently physical form, we had everything that makes us human. When you think of the ways that the mobile hunter-gatherers of the American Great Basin lived, you are also thinking of something very close to how our common ancestors in Africa lived 50,000 years ago. All of us are, and were, human, not "cavemen."
Our prehistoric ancestors began as highly mobile hunter gatherers, spread throughout the world, and adapted to mobile conditions (and quickly changing conditions with the end of the Pleistocene, ca. 12,000 years ago). Some groups began agriculture, became sedentary, and began to form towns and eventually cities, while other remained mobile and nomadic, some adopting animal husbandry and some retaining hunter/gatherer lifeways...and there were many steps in between all of these points that various human societies adopted. In each case, though, the form of culture developed in response to local environment.
And this seemed to be where the fellow asking the question was having a problem. He seemed to think, based on how he phrased his question, as well as the follow-up comments that he made, that a lack of farming was a "caveman" trait. That I was talking about Native Americans 250 years ago, not early people on the African savannah 50,000 years ago...and therefore the people about whom I was speaking clearly must have been engaged in cultivating crops, and he was unwilling to accept the word of myself or anyone else who had actually studied the matter to the contrary.
But, of course, the fact of the matter is that humans will do what their environment** demands. For some, this means that agriculture becomes necessary. For others, it does not.
*This is definitely a spectrum, too. It is common for us to think that there is some sort of clear line where a culture "becomes" agricultural. But where does that line fall? Clearly, people who plant annual crops and engage in irrigation and fertilization are farmers. But what about people who scatter plant seeds but don't prepare fields or irrigate them? What about people who don't intentionally plant seeds, but prune or otherwise tend to plants to promote the growth of some over others? What about those who burn areas of field or forest to promote the growth of disturbance vegetation? There are many steps on the way from forager to farmer, and it's not necessarily clear where one ends and the other begins.
**This includes both the natural environment and the social environment.