>>17891442
>>17891253
>>17892409

Different Anon, but compared to the other Hominids (not our immediate ancestors the Cro-magnons) the Neanderthals were still extremely intelligent, they just weren't smart "enough".
Homo Erectus persisted for over 2 million years with a material culture of possibly less than 5 items and no clothing. Neanderthals meanwhile: used pitch to glue things together, could boil water in a birch bucket, milling stones for acorns and pine nuts, made flutes, cave paintings, and while they didn't have tailored clothing (as far as we know atm) they did still strung together beads, and accessorized with feathers, teeth, etc.

This Anon: >>17891709 talks about Neanderthals possibly being "autistic" due to their rigid behaviors, but this aversion to change is probably more normal than we think. We need to remember that for 300,000 years we weren't doing too much of anything, and that even then only a handful of our own cultures developed anything resembling civilization - tons of people never left the bronze age, or even the mesolithic.
I vaguely remember an interview with some Hadza people in Africa about the bows they made. The interviewer was curious if the Hadza people had any unique insights, but they literally built bows and arrows like a bird would build a nest: no thoughts, head empty, it was a tradition that had been drilled into them with minimal deviation.