Why does nodding of the head signify Yes and shaking of the head No?
Also, try "psychology".
From Google:
As to countries which practice the usual nod/shake arrangement, nodding likely originated as an informal bow. Bowing has since disappeared, but the humble nod remains. Shaking the head probably started as an exaggerated form of turning away from something undesirable.
More specifically, when a baby does not want to eat something, s/he moves his/her head from side to side to avoid the food. This is generalized into the no response.
The cultural significance of nodding and shaking the head varies across different regions and societies. However, in many parts of the world, nodding the head is generally understood as a gesture that signifies agreement or affirmation, while shaking the head represents disagreement or negation.
The origins of nodding and shaking the head can be traced back to basic human physical responses. Infants naturally nod their heads when they are content or satisfied, and they tend to shake their heads when they are uncomfortable or displeased. These innate movements likely form the basis of these gestures being used to convey agreement or disagreement.
Additionally, nodding and shaking the head are also influenced by cultural and social factors. Over time, certain gestures become associated with specific meanings and are reinforced through social interactions and learning. For example, in Western cultures, the orientation of a nodding motion aligns with the up and down movement of the head for a "yes" response, while shaking the head side to side corresponds to the left and right movement commonly associated with a "no" response.
It's important to note that there are exceptions and variations to this general understanding. In some cultures, such as Bulgaria and Greece, nodding may indicate disagreement, while shaking the head can convey agreement. Understanding nonverbal communication in different cultural contexts requires an awareness of these variations.
To delve deeper into the cultural origins and meanings of nodding and shaking the head, it would be helpful to study anthropology, sociology, or social psychology. Reading books, articles, or research papers on these subjects can provide a more comprehensive understanding of how these gestures developed and gained their widespread interpretations.