Final answer:
The scientific study of stress started in the 1930s with substantial contributions from Walter Cannon. Later, Hans Selye's work was also fundamental to the field. The term became widely used in the public lexicon by the 1970s and has been notably researched for variations among demographics by Cohen & Janicki-Deverts.
Step-by-step explanation:
The term stress began to appear in the scientific literature concerning the human condition in the 1930s. Notable early contributions to the field of stress research were made by physiologists like Walter Cannon, who identified the body's physiological reactions to stress. However, it wasn't until the 1970s that the term stress entered the popular vernacular.
Another significant figure in the evolution of stress research was Hans Selye, who specialized in the area. In fact, Selye's native Hungary honored him in 2009 with a commemorative stamp. This recognition came alongside the 2nd annual World Conference on Stress, highlighting his pioneering work in understanding stress and its effects on the human body.
Research by scientists such as Stephen Cohen and Doug Janicki-Deverts demonstrated the variations in stress levels among different demographic groups from the 1980s to the first decade of the 2000s, notably documenting an increase in stress over this period potentially linked to economic pressures and societal changes.