Reading Aloud and Vocabulary Acquisition

In this weeks article, two researchers, Edna Greene Brabham and Carol Lynch-Brown, studied the effects of three different read-aloud strategies on the acquisition of vocabulary in first and third grade students. The three different read-aloud styles are "just reading," "performance," and "interactional." At first glance, I had a hunch that "just reading" would not be very effective. However, we have talked a great deal in class that read-alouds do help acquire vocabulary at any age and in any content area, so I was anxious to see what the authors had discovered. 
I found that this lesson is very relatable to me as a pre-service teacher. When thinking of elementary education, it is fairly natural that one would assume read-alouds would be involved in the weekly curriculum. However, I feel that it is less known the read-alouds can be used for so much more than gaining a child's interest in reading (which is also important). This study highlights how effective read-alouds can be, especially when dealing with vocabulary. This is important for pre-service teachers to be aware of due to the fact that by simply manipulating the way that a book is read-aloud, the more effective that text will be to help the students understand more than just the plot. In the results, Brabham and Lynch-Brown found that just reading was the least effective, followed by performance, leaving interactional to be the most effective.
One thing I learned in the article that was interesting to me was that when a teacher stops to have class discussions throughout the story, the comprehension of the story is not compromised. This was good to know because I feel that in order for a book to be used effectively to its fullest, conversation should be a key component. However, the study was not technically conclusive on which read-aloud strategy was "best." So, my questions for these authors are: Although all of these strategies were not the best at vocabulary acquisition, are they good for other strategies in the classroom? and this study only included first and third graders, so how would these read-aloud styles work in adolescent students?