Explain to me this sentence please

Masters, read this sentence please:

A study by Allan Kennedy found that "subjects viewed the humorous introductory speech as significantly more effective, enjoyable, and interesting".

I can not analyse grammar in this sentence. Is there any mistake in this sentence? Maybe AS must be changed into WERE like this??

A study by Allan Kennedy found that "subjects viewed the humorous introductory speech WERE significantly more effective, enjoyable, and interesting".

The same question with this sentence:

A study by J. Douglas comparing humorous and nonhumorous information lectures did show significantly better student retention of the humorous lecture.

I can understand the meaning of this sentence but I dont understand Grammar here. Maybe here is a english grammar structure that I dont know??

Thanks in advance.

The basic structure of the sentence is this: The study (the subject) found (the verb) that...(relative clause). Inside of the relative clause there can be as many subjects, verbs adjectives, etc. as you can think of. These do not change the basic meaning that the study found something.

I would simplify this sentence as follows:

A study found that people liked funny introductions better than serious introductions.

I could see that structure mykwener, I confuse by as significant more except structure as adj as, we have another one as adj more, right?
In the second sentence, better student here is used as adj modifying retention??

In this case, more is functioning as an adverb of comparison.

A study by Allan Kennedy found that "subjects viewed the humorous introductory speech as significantly more effective, enjoyable, and interesting" [than the serious introductory speech].

The structure is: as+adverb (significantly) + adverb of comparison (more) + adjectives.

In this sentence, the word as is expressing a condition. You could substitute the infinitive phrase to be without changing the meaning of the sentence.

Yes, both better and student are adjectives modifying retention.

I already understand, thank you so much, master mykwyner! :)