Neanderthals had similar sized skulls/brain cavities – so they might have been smarter. They were tool users and had fire – so they were on par with homo sapian-sapian.
According to 23&me – modern humans of european descent have between 1 and 4 % dna from neanderthals – with the average person of european descent having 2.7%. I’m above average by a smidge… < insert grunt here > … perhaps I should pluck my eyebrows thinner to hide this. LOL
My husband likes to tease me that I’m more neanderthal than him. I always threaten to bop him over the head with a club.