What did Darwin postulate about emotional expressions?

Charles Darwin postulated that emotional expressions are universal among humans and are not learned but rather are inherited behaviors that have evolved because they had adaptive value. In his seminal work, "The Expression of the Emotions in Man and Animals" (1872), Darwin proposed that emotional expressions were similar across cultures because they originated from common ancestors. He argued that these expressions were biologically innate and evolved through natural selection because they served important communicative functions, allowing individuals to quickly convey a wide range of information about their emotional states, intentions, and reactions.

Darwin suggested that certain emotional responses are so deeply ingrained that they are often displayed in similar ways by people from diverse cultures, as well as by other animals. For example, the expression of anger might involve furrowing the brow, flaring the nostrils, and baring the teeth, which can be observed across human societies and in some non-human primates.

He also explored the principle of antithesis, where opposite states of mind lead to contrasting body movements or postures. For instance, a submissive individual might lower their gaze and adopt a smaller body posture, which is the opposite of the expansive and direct stance of a dominant or aggressive individual.

Darwin's ideas on emotional expressions laid the groundwork for later research in psychology and ethology (the study of animal behavior), influencing our understanding of the biological and evolutionary basis of emotions. His work has been expanded upon by numerous researchers, and while some of his ideas have been challenged or refined, the core concept that many emotional expressions have an evolutionary basis is widely accepted in the scientific community.