A Stiff-necked people

Summary: Does the Torah indeed indicate, in Ki Tisa, that physically thick-necked people are stubborn?

Post: In parashas Ki Sisa, we read (32:9):

ט  וַיֹּאמֶר ה, אֶל-מֹשֶׁה:  רָאִיתִי אֶת-הָעָם הַזֶּה, וְהִנֵּה עַם-קְשֵׁה-עֹרֶף הוּא.

9 And the LORD said unto Moses: 'I have seen this people, and, behold, it is a stiffnecked people.

The meaning is that they are stubborn. On this pasuk, Ibn Caspi writes:

"It is known that one whose neck is thick is also stubborn."

Is Ibn Caspi appealing to physiognomy? Until fairly recently, it was regarded as a scientific discipline. Aristotle discusses physiognomy, and it also appears in the Zohar.

Looking to Aristotle, On Physiognomy, as a guide in this matter:

Here is a more recent work, regarding Characterology:

Of course, this is a pseudo-science. So, what are we to make of Ibn Caspi? It strikes me that three answers are possible.

(1) Ibn Caspi was taken in by erroneous contemporary science.

(2) Ibn Caspi was speaking of the common perception. (I don't think ידוע implies this, but we can supply this explanation on his behalf.) And Ibn Caspi often states that dibra Torah kilshon bnei Adam, that the Torah speaks in the language of people. A related approach would be to say this is merely an idiom, based on the common perception.

(3) Perhaps one could argue that this is indeed an observable phenomenon, at least in those days.

It seems that psychology would play a role in this. Someone presents an intimidating appearance, or seems loutish. Or else people who work in certain professions (e.g. butchers) that require a strong and bulky build also foster certain character traits.