According to the professor, why did method acting take off in the United States?

Professor (female)
   Who’s seen Rebel Without a Cause?You know, the classic James Dean movie...the one where he plays a troubled teenager. Dean gives an intense performance, doesn’t he? He broods, he screams, he looks wide-eyed and angry. It’s like he’s not acting--it’s like he actually is the character. Well, Dean was using a famous technique called method acting. And, uh, that’s what we’re going to talk about today.
   Method actors try to understand the psychology of their character. They want to personally identify with the character they’re playing. Here’s an example of what I mean. Q16 If you were playing a character whose grandfather died, you would want to recall a similar experience in you own life-like the death of someone you knew--and try to relive that experience...replicate those emotions onstage. Is that clear?
   Q12 Good. So, uh, today I’ll be discussing two major figures in the development of method acting. First, there’s Constantin Stanislavski, a Russian actor and director who essentially laid the foundation for method acting. Then there’s Lee Strasberg, an American teacher and director who, urn, guided by Stanislavski’s ideas, introduced method acting as we know it today.
   Q13 First, to understand Stanislavski’s ideas, we’ve got to look at Russian theater of the time... the early 1900s. Czar Nicholas ll’s censorship policies really stifled creativity, Um...nobody was willing to experiment with new material in the theater. They stuck with things they knew would be acceptable--plays translated from French and German melodramas or vaudevilles. Really, there wasn’t much room for creative expression or experimentation because actors basically specialized in a certain kind of role and had to follow these, um, set formulas for that role. Roles like...the amorous lover...or the clumsy father.They were always played the same way.
   Q13 Stanislavski wanted a change--he wanted to raise the standards for actors and get away from this predictable theater, Q15(C) So he started studying the techniques of actors he admired and developing some theories and exercises on how to act.These came to be known as the "Stanislavski system." Q15(A) One principle of this system was that the actor must use his or her own experiences to make the role real--more than just a performance. Instead of imitating emotions, Stanislavski wanted actors to try to experience the emotions of their characters more fully. He saw this as introducing "truth" to theater, Um, this idea was appealing, especially in the U.S., and it spread quickly. Drama schools adopted it, simplified it, and began teaching it to their actors. Q14 Pretty soon, Stanislavski’s method was a major part of American theater.
   Why did this happen? Well, you’ve got to understand that, urn, during the twentieth century, there was a kind of cultural change occurring in the United States. it had to do with American society’s growing interest in originality ,..and individuality. Q17 Um, I don’t want to get too far off the topic here, so suffice it to say that as a result of these changes, Americans were rejecting the idea of imitation...um, fakeness--in favor of authenticity.
   Q14 So there was a growing desire for, for authenticity in all aspects of American culture, including theater. This, urn, cultural shift really created the right conditions for Stanislavski’s theories about acting to take hold. Through the beginning of the twentieth century, his ideas spread and evolved in American theater until the 1940s and ’50s, when a New York organization called the Actors Studio essentially...um, they evolved the Stanislavski system into what we now know as method acting. Lee Strasberg, the director of the Actors Studio in the ’50s...he gets much of the credit for developing this technique, urn, which is sometimes shortened to "the Method:"
   Like Stanislavski, Strasberg believed that actors should try to empathize with their characters in order to give authentic performances. He also encouraged actors to focus on their own pasts--their own experiences...to find emotions and experiences that fit the context of the role and could be brought to life onstage. But Strasberg took Stanislavski’s idea further. He wanted emotions from an actor’s past to be relived exactly, in order to come across as authentic during a performance.Q15(B) He called memories like these, urn, which were useful for reliving during a performance, "affective memories." So, according to Strasberg’s method, actors needed to store up a variety of affective memories that they could relive when necessary to produce a range of emotions. Q15(D) These teachings changed the course of American theater, and some of the most famous Hollywood actors were students of Strasberg, like Jack Nicholson, Marlon Brando, James Dean, and AI Pacino.