>>12746510
>Charles Darwin believes that this has to do with our primitive instincts and our nursing habits. When babies seek food they tend to lean their head forward in search of their mother’s breast. However, when they are not hungry, they shake their head from shoulder to shoulder trying to avoid the breast. This instinct continues into our life and that’s why we nod for yes and shake our heads for no.
>We need to clarify here that, even though this explanation makes sense, it’s nothing more than a theory. Yet, it’s a theory that most scientists seem to agree and it’s even backed up by the fact that people who are born deaf and/or blind will use the same gesture.