Mass media plays a unique and important role in shaping our society; not only does it translate society’s progression and present them into media that we consume regularly, but also promote and reinforces social reality and values. As De Lauretis states, “cinema is directly implicated in the production and reproduction of meanings, values and ideology”. By looking at the evolution of definition of masculinity influenced by key historical events, and analyzing how masculinity is portrayed in films, we can see that masculinity has been undergoing a stage of cultural transition towards new modes of masculinity that challenge the rigidities of male gender identity in previous decades.
Traditional meanings of masculinity
During the early years of this period of time in the United States, masculinity was seen as a valued status as they were favoured in any situation or aspect in life. To be masculine, it meant that you were a white, aggressive, and competitive male that would take on the role of provider in a family. In addition, muscular physiques, sexual prowess, and emotional control were dominant characteristic of masculinity. Films that were made during this period of time not only portrayed men with such rigid masculine identity, they demonized other “abnormal” variants of masculinity, and emphasized the concept of homosexuality as a sin. Such conformist view on sexuality and gender role was reflected in noir films especially in the postwar period, as Steven Cohan pointed out that it revealed "repressed wartime trauma and the situational development of feelings of intense male-male intimacy, homosocial bonds that had to be suppressed in the postwar social order." One example was Dead Reckoning by John Cromwell (1947) which emphasized the impossibility of male-male bonds and the inherent impasse between men and women in patriarchy, which served to impose a sexual normativeness on the American postwar generation.
In the 1960s and 70s many subjugated groups began to speak out against social constraints, so too did men. These major social movements have altered the meaning of masculinity in the United States after the 1960s. These movements include the women's liberation movement, gay liberation movement, and the men’s movement.
The women’s liberation movement
This movement gave a voice to feminists to question the patriarchal society and their role and rights in society in comparison to men. Not only did they began to reshape the values of American society but they also helped men to evaluation their relationships with women, their parenting, and their role within the home and society.
The Gay Liberation Movement
The gay liberation movement in 1969 promoted gay rights and prerogatives, they also fought to remove homosexuality from the list of mental illness, which was later successfully removed by the American Psychiatric Association in 1974. These groups of activists have affected emerging concepts of masculinity, which is a “…critique of the Western taboo against male expression of intimacy and affection raised unresolved issues for all men, regardless of sexual orientation." This movement helped to clarify the sex-role concepts, shaping the emerging meaning of masculinity.
The men’s liberation movement
This movement placed a greater emphasis on a form of masculinity where emotionality is an essential value for "real” men. Men argued that social expectations and norms have forced men into rigid gender roles, limiting their ability to express themselves and restricted their choice in behavior regarded as socially acceptable for men.
Though majority of films produced at this period of time still portrayed a “real man” as one that is stoic and stifles emotion, we were beginning to see films and producers explore and challenge the traditional definition of masculinity. One example was First Blood (Kotcheff 1982), where the hyper-masculine protagonist who repressed his tears throughout the entire film, ultimately let out his emotions, demonstrating that crying is not a sign of weakness and vulnerability, but rather, a sign of bravery. 
Early 21st century till now
The definition of masculinity in the twenty-first century masculinity is leading towards a more balanced and achievable form of masculinity. Traditional notions of masculinity are being challenged, overturned, and evolved. These changes are reflected in films as we saw the increased expression of fluid of masculinity in American popular culture at the turn of the new millennium and beyond. Rather than assuming the traditional form of stoic and unemotional provider, the protagonists in various films grapple with their identity as a man in modern society. With male identity crises displayed so prominently in film, this development signals a cultural shift in the definition of masculinity. 
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