How do anthropologists link prehistoric, pre-writing archaeological findings together into units?

Question

Small chipped grooved rocks found all over America became 'Clovis culture'. Stone faces and daises unearthed in Veracruz/Tabasco became 'Olmec civilization'. Lines carved into an expanse of desert and pottery uncovered there became 'Nazca culture'.

Anthropologists are great at lassoing together findings from various locations and times; these groups invariably become viewed as units, with one people speaking one language living by one set of beliefs and customs. If one lists the civs of ex-Yucatan Mesoamerica as 'Olmec, Teotihuacan, Toltec, Aztec', there is a sense that the Olmecs were a civilization like the Toltecs & the Aztecs.

What is the standard by which anthropologists annotate the debris of history into groups? Why do these groupings invariably get interpreted as one unit/people, as opposed to several? If in 3000yrs our descendants dig up F-80 and MIG remains in Korea, will America and Russia end up grouped together as the 'great Korean steel-wing civilization'?

Answer 1

I'm not an expert, but it's because of similarities in the groups of artifacts recovered from different places.

The objects, how they're made, what they were used for, and especially the decorative elements (which are completely arbitrary, unlike the relevant stuff -- that is, all containers need to have a containment aspect, and a way to get what they contain into them; but how people pretty them up is completely cultural).

So when you see similar things used as decorative elements (particular species of bird, for instance), and similar configurations, and drawn in similar styles, it's most reasonable to conclude you're looking at artifacts from a single culture.