Let’s say you have a village of 150 people (Dunbar’s number). What sorts of technologies would they have? The basic human needs are shelter, food, and water. Shelter means houses, food means hunting/agriculture/domestication, and water means either a way to catch and hold rainwater or settling close to a river or stream. So the starting point of our hypothetical village is one near a river with some hand planted crops. At the start of our simulation (powered by the imagination), our people live in the crudest form of houses. They know nothing of agriculture, only that if they throw their left over food at a certain spot that more of it will grow.
For the sake of argument, we’ll say that these people are as smart as we are. This wouldn’t actually be the case, because nutrition is highly correlated with intelligence, but making this simulation more complex than it needs to be isn’t really the point. We’ll also suppose that they have no cultural inhibitions about experimentation; if a member of the village decides that he wants to put a few of the seeds under the ground instead of just dropping them in the dirt, no one will stop him. The only caveat is that no one will do anything which risks destroying the village. Their reproduction will hit almost exactly replacement numbers (though pregnancy will be common, because infant mortality will be horrifically high). Finally, we’ll suppose that there are no other villages, and that none of the villagers are predisposed to defecting and forming a new village anytime soon.
Initially, there are a limited number of jobs that a person can hold in the village. The plants grow without interference, so there are no farmers. Since this method of agriculture doesn’t provide much food, the men hunt. Their weapons are crude; nothing more than sharp sticks and heavy stones. The women stay in the village and care for the children. Meat is eaten raw, supplemented with fruits and vegetables that have been grown or foraged.
When there are storms, lightning occasionally strikes, and when the villagers go to investigate – in this manner, fire becomes known to them. Since there is a lot of free time, especially at night, a few of the men set out to see if they can make fire. For all they know, fire might only be a product of lightning, but they’ve seen that fire can be made from fire, and they’re naturally inquisitive, so they try. Eventually someone manages to make fire by rubbing two sticks together, and from there fire is cultivated until nearly anyone in the village with enough patience can produce it. Fire keeps them warm, makes them able to work in the night, and they find that putting the meat over the fire makes it taste better – with the added effect of making them less prone to sickness.
At the same time, agriculture is forming. An enterprising villager puts the seeds below the ground and finds that they grow much more readily than when they’re left on the surface. He also finds that the plants thrive on constant water, so on days when it doesn’t rain, he scoops up handfuls of water and runs them over to the plants. Since this is a laborious task, the villager looks for some way to carry water more efficiently – a number of other people need containers too, for excess food and so they don’t have to go down to the river for water. This possibly means the creation of pottery, which at its most basic is simply some mud formed into something and left to dry.
So by now the villagers have figured out that they can make their lives better through research and development. Enough experimentation eventually leads to the scientific method, though most of these primitive technologies can also be reached through chance. At any rate, our enterprising farmer has made crop production into something that’s no longer passive, and since this is a more productive method of food gathering than foraging, we now have excess labor. Some of this goes to the fledgling production of pottery, some goes to art, or possibly religion, and some is simply wasted on having fun.
Meanwhile, our hunters keep bringing back animals, and our villagers eventually learn which parts are good to eat, which parts are not, and which can be used for other things. Splintered bones can be used for weapons, or for shaping pottery, and some of the inedible stuff can be used for fertilizer. The animal fur, once the flesh has been removed, can keep a person warm at night. Because these villagers are about as smart as us, they figure out that animals must reproduce in roughly the same way as humans do – they learn this from watching the animals, and form extrapolation. One particular hunter, who is getting older and not as fit, realizes that they might be able to capture some animals and slaughter them when the meat was needed, instead of going through the hunt and possibly bringing them close to starvation if they have an unlucky streak. It is later figured out that these animals can simply be raised by the village instead of hunting them. This frees up more labor.
Now we have to make some assumptions about the resources available to these people. For the sake of the simulation, they will have access to pretty much any metal they want, as well as stone and trees. We also have to make some assumptions about how they spend their excess labor; some of it has to be going to improving their condition instead of leisure.
They find copper, shining in their river. They first use it for art, but upon realizing that it can be banged into any shape by using a stone, and that it is lighter and just as sharp as their bone weapons, they start using it to hunt. If they can get enough of it, they start finding other uses, like in farming. One day someone drops some copper into the fire, and they find that this makes it more malleable. If they can get it hot enough, it melts, unlike their stones. They find that they are able to do this with some other metals that they find in the river, and from there are able to understand the elemental nature of the world.
Meanwhile, someone has discovered that fire is better for making pottery than the sun is, and with some experimentation they discover the right temperatures to bake things at for the best hardness/brittleness ratio. They also work on developing a kiln, which comes out of their attempts to make a very hot fire by building walls around a normal fire. It is also in this way that they discover fire needs air, and they make the first bellows, which is nothing more than a fan in push air into the fire.
The villagers look around them, and see what they’ve made. They have fairly advanced farming, with crop rotation, fertilizers, pest control, and irrigation. They have a number of domesticated animals, whose jobs range from food to pack animal to ratter to hunter. They have the pottery wheel and the kiln. They have a doctor, who is not very good because of the limited experience that a population of their size offers. Hunting is done much less now, but they have nets, spears, and various other instruments to kill animals. Their huts are much cleaner and more structurally sound than they were before, and are reinforced with wood.
There are a number of things that these people will never invent, simply because they have no need for them. They will never invent a building more than two stories tall. They will never invent internal combustion. They will never invent the computer. They will never invent the lightbulb. They will never perfect medicine, because most of the more rare diseases will occur only once, if that, in a doctor’s lifetime. Because all knowledge is passed down from master to apprentice, and because all communication is done within the village, they will never invent writing.