The Sapir-Whorf hypothesis, concerning the way language and culture

1. Based on - right idiom.

2. After "psychology, " we need to point some attribute. In another case the next part will be independent clause.
So option B, for example, is out because before their we need semicolon, since "their basis being in empirical field-work among native American tribes, such as the Hopi" seems like an independent clause (and moreover wrong one).

3. D is the only good option here.
But can someone explain this part: "as it was" - why it is here, for what?

The Sapir-Whorf hypothesis, concerning the way language and culture determine thought, exercised a significant influence on cognitive psychology, based as they were on empirical field-work conducted among native American tribes, such as the Hopi.

A based as they were on empirical field-work conducted among native American tribes, such as the Hopi. --> what is the antecedent of they

B their basis being in empirical field-work among native American tribes, such as the Hopi. --> same as A

C because having a basis in empirical field-work among the native Americans such as the Hopi tribes. --> because should be followed by a complete sentence

D based as it was on empirical field-work conducted among native American tribes, such as the Hopi. --> correct

E for it being on empirical field-work with native American tribes, of which Hopi among others. --> award

Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.