The difference between laboratory experiments and field experiments is not the number of subjects, but the place where they are conducted—the lab or the outside world. Lab experiments are more easily controlled, whereas field experiments are more realistic.

A variable is described something that varies between people or objects—in this case, temperature and aggression are the variables. The “independent variable” (IV) is the variable that is manipulated by the researcher (temperature) and the “dependent variable” (DV) is the variable that changes as a result of a change in the IV (aggression). A “hypothesis” describes the relationship between variables and is generally what the researcher predicts will happen (i.e. “as the temperature in a room increases, a measure of the subject's aggression will increase as well”). Last, a “theory” is a principle or set of principles that explains a phenomenon.

A variable is described something that varies between people or objects—in this case, temperature and aggression are the variables. The “independent variable” (IV) is the variable that is manipulated by the researcher (temperature) and the “dependent variable” (DV) is the variable that changes as a result of a change in the IV (aggression). A “hypothesis” describes the relationship between variables and is generally what the researcher predicts will happen (i.e. “as the temperature in a room increases, a measure of the subject's aggression will increase as well”). Last, a “theory” is a principle or set of principles that explains a phenomenon.

"Industrial-organizational psychology" focuses on applying the scientific study of individuals and groups to optimizing workplace performance. Psychologists in this field typically work for large corporations and help them to improve areas including employee satisfaction, employee retention, and productivity. 

Wilhelm Wundt, regarded historically as one of the founders of modern psychology, introduced his structuralist perspective in the late 1870's, as the first major psychological perspective. In direct response to this, the school of functionalism in the later 1880s was introduced by William James. Gestalt psychology was first introduced in 1890 by Christian von Ehrenfels, though the idea of gestalt can be traced back as far as David Hume and Immanuel Kant. Last, evolutionary psychology did not begin to differentiate itself from mere evolutionary biology until well into the 20th century, with most historians placing the actual date around the 1960's-1980's (Donald Symons likely being the first dedicated evolutionary psychologist in the 1970's).

"Industrial-organizational psychology" focuses on applying the scientific study of individuals and groups to optimizing workplace performance. Psychologists in this field typically work for large corporations and help them to improve areas including employee satisfaction, employee retention, and productivity.