Final answer:
The primary force behind the consumerism of the 1950s was economic prosperity, which, aided by technological advancements, mass production, marketing, advertising, and the expansion of credit, heralded a new era of consumer culture.
Step-by-step explanation:
The primary force shaping the new consumerism and mass popular culture of the 1950s was the dramatic economic growth and prosperity resulting from technological innovations, mass production, and widespread marketing and advertising efforts which led to increased disposable income and demand for consumer goods. This era saw a significant shift from spending on necessities to spending on wants, with the advent of credit becoming a key facilitator.
Advances in credit including the introduction of the credit card and installment plans enabled more Americans, particularly those in the middle class, to spend confidently with the expectation of continued economic prosperity. Products were not just sold; they were marketed as embodiments of dreams and hopes, epitomized by the slogan 'Sell them dreams.' The goods produced and the advertising strategies implemented convinced Americans that accumulating material items equated to achieving the good life, fueling the consumer culture further.
The mass media also played a crucial role, with the proliferation of newspapers, magazines, radio, and movies shaping a national mass culture and disseminating consumerist values. This new mass culture celebrated a focus on leisure and acquisition, notably through the allure of Hollywood and the influence of national sports icons. In summary, the 1950s consumerism was fueled by a combination of economic prosperity, credit expansion, mass production, and pervasive marketing and advertising strategies which together forged a culture that prized consumer goods as the pinnacle of success and personal fulfillment.