Any other way that information can be passed between people. Common examples are the use of facial expressions and body language, but can also include how someone talks such as tone and volume
New-born babies (Neonates) and the sensory deprived provide useful subjects, they haven't learnt body language from visual observation, so their behaviour must be instinctual
As neonates show these expressions before they observe them modelled, this is evidence for non verbal behaviour being innate, that genetics provide humans the innate ability to smile from birth
A behaviour is adaptive if it increases the chances of survival. Human babies show a range of body language designed to cause appropriate caregiving behaviour from the adults around it
Research in neonates and the sensory deprived shows the presence of body language at birth, this indicates a genetic origin, selected for by evolutionary pressures
Cross cultural Research such as Yuki, demonstrates there is variation between groups of people, if human body language was just evolved it should be universal between all
People who share a social status level will have a smaller area of personal space between each other, compared to high and low status people who will keep a larger distance between each other