I say this sort jokingly but this qualifies as possibly the ‘worst HBD article ever’:

Why Do Many Geniuses Have a Large Forehead?

There is a lot wrong with this short article

But quite a few super geniuses with IQ’s of 160–200 have extremely large heads. Christopher Langan had to special order a motorcycle helmet made specifically for him because his head was so big. The manufacturer told him that only 1 out of every 3.3 million people had a head as big as his. He has some videos on Youtube. If you look closely at him, you might notice that one thing that is remarkable about him is that he does indeed have a huge head.

Having a big head as measured by circumference, as in the case of Christopher Langan, is not the same as having a big forehead. The reason is, head circumference and volume is a function of width, height, and length of the cranium. Height is the most uniform, so much so that there does not exist a classification for it. Width varies more, and there are three classifications:

Northern Europeans and Blacks tend to have narrower skulls, whereas Semites and Asians have wider skulls.

Then there is also length, which varies the most and is the most closely related to IQ in terms of head circumference and brain volume. A longer skull almost always confers with higher IQ, although sometimes a broad but shorter one does too, as in the case of brachycephalic Orientals.

The ‘egghead’ appearance has less to do with IQ and brain volume, but rather is an illusion due to frontal balding. Because skulls are oblong shaped, tipping the head forward, combined with frontal balding, creates the appearance of having a really large forehead.

See this example of a before and after photo of a hair transplant:

For what it’s worth, from what I have observed, some really smart people tend to have low but broad foreheads, sorta like a skillet. The low forehead belies the elongation of the skull and the width. For example, Sylvester Stallone, who has a low and broad forehead (the exact opposite of an ‘egghead’) and purportedly an IQ of 160.

Before your call bullshit, such a score is plausible. He actually wrote the screenplays for those movies he starred in; 99.9% of people just assume he only acted in them. That requires a lot of talent (most average-IQ people if they attempted to write anything resembling a screenplay would not get past the first page and it would be terrible), and what is especially amazing is he wrote Rocky in his early 20′s without any professional creative writing experience, suggesting autodidacticism, which is a high-IQ trait.