yes, i believe our brains have shrank by 10% in the last 5,000 years alone. so a 20-30% lift isn't a big leap. also, if you read the wikipedia article it ment

yes, i believe our brains have shrank by 10% in the last 5,000 years alone. so a 20-30% lift isn't a big leap. also, if you read the wikipedia article it mentions that they were not a separate species, but human and the size is highly debated