Humans, somewhere along the way from Australopithicus to Homo sapiens have developed a linguistic/conceptual based mind (with developments of the Broca's region, Wernicke's region, neocortex, amongst other brain regions and networks. This linguistic mind has changed the way human behavior functions from other animals. It gives humans the ability to create complex hierarchical thinking. We still have very basic instincts (e.g. eating to get rid of hunger, warmth, a drive towards pleasure, etc.) but most other behavior any more complex than these basic drives, is based on linguistic-cultural origin and not instinct. — schopenhauer1
I would submit that the
language instinct is at the heart of your "linguistic-cultural" behavior. Besides language, general cultural features such as hierarchy-formation, domination of individuals and groups over other individuals and groups, story-telling (composing narratives out of experience), eating together, music (nothing specific, just the employment of music and rhythmic motion (dance) in some form, religious behaviors (again, nothing specific), and so on
all demonstrate instinct.
At the most biological level, humans share with the rest of the animal kingdom a regular pattern of sleep and wakefulness, mating, breast feeding, foraging for food, nest making, defensive hostility (to protect the group), etc.
If you add the basic biological stuff to rhythmic movement and melodious sound making, language use, story telling, eating behaviors, dominance behaviors, religious behaviors, you have named a significant share of human behavior.
That still leaves room in human behavior for novel, spontaneous, never-seen-before-on-TV behaviors and patterns and learned behaviors.
The reason that human behaviors and cultures are consistent across the board (in general form, not in fine detail)--the reason why we are more similar than we are different--is instinct. It's our instincts that give basic form to human behavior.
The latest findings indicate that we have been our species, homo sapiens, for 300,000 years. (Remains found in India, Israel, and Morocco from 200,000 to 300,000 years old all have very modern teeth.) It's safe to say that we didn't make it over 300,000 years, and longer from our previous species to homo sapiens WITHOUT instinctual guidance.
If you look at tool making, there were very long stretches where the same tools were being made. There didn't seem to be a lot of day-in day-out learning leading to improved tools. It was the same thing over and over--until at some point that stopped and tools started to vary, become more specialized, be made out of different materials, and so on. That development seems to bring us closer to the "modern era" which began maybe 40,000 years ago.
I base my approach on evolution. We didn't just evolve as humans with no connection to pre-human animals. Humans evolved from earlier animals. The features of our behavior have ancient roots, just as the biology of our bodies have ancient roots. Even giving a large role for evolution leaves plenty of room for learning and novel, spontaneous behavior. If modern humans were found from Morocco to India 300,000 years ago, we were clearly a curious species--we kept going to the top of the next hill to see what lay beyond.
So it's both instinct and culture.