Darwin's evolutionary explanation
- Non-verbal communication is everything you pass on without words, from facial expressions and eye contact to posture, gesture and how close you stand, and the question is where it comes from.
- Darwin's (1872) theory of evolution answers that it is inherited rather than learned.
- The argument runs through natural selection, so a signal that helped an ancestor survive and reproduce was passed on to their offspring.
- Behaviour that survives in this way is described as adaptive, meaning it earned its place by being useful.
- This makes non-verbal communication a nature explanation, since the signals arrive with you rather than being taught.
How signalling emotion helped survival
- A fear expression widens the eyes, which lets you take in more of what is around you and at the same time tells everyone nearby that there is danger.
- An anger expression bares the teeth and lowers the brow, which can drive off a rival before a fight starts and before anyone is hurt.
- Both signals work faster than speech, so a group that could read them reacted to threats sooner than a group that could not.
- Individuals who both produced and read these signals well were more likely to survive long enough to reproduce, so the ability spread.
Example
- Crossing a quiet car park at night, you hear footsteps behind you and your face is already in a wide-eyed fear expression before you have decided you are frightened.
- Anyone walking with you reads the danger from your face and speeds up too, without a word being spoken.
- That the expression beats your own decision to it is exactly what an inherited signal should look like.
What the theory predicts
- If the signals are inherited, they should be recognisable in every human group rather than only in the one you were raised in.
- They should also appear before there has been time to learn them, so newborns should produce them.
- They should appear even when copying is impossible, so a person blind from birth should still produce recognisable expressions.
Strengths and weaknesses of the theory
- One strength is that basic expressions such as happiness, fear and anger are recognised in cultures with almost nothing else in common.
- A second strength is that babies smile before they could have copied anyone and people blind from birth still produce recognisable expressions, neither of which learning explains.
- One weakness is that gesture meanings and comfortable distance plainly differ between cultural groups, which points to norms being learned rather than inherited.
- A second weakness is that Yuki et al. (2007) found Japanese participants leaning on the eyes and American participants on the mouth when judging the same faces, so reading a face is at least partly learned.
Common Mistake
- Do not write that all non-verbal communication is innate, because the evidence on gestures and distance flatly contradicts it.
- The defensible position is that some signals are inherited while the rules for using and reading them are learned.
Turning this into marks
- Name Darwin (1872) and say the signals are inherited, adaptive and shaped by natural selection.
- Pair each side with named evidence, such as blind-from-birth expressions for and Yuki against.
- The mark most often lost is the conclusion, so end by saying which way the evidence leans and why.
Self review
- What does Darwin's theory claim about the origin of non-verbal communication?
- Explain how a fear expression could have helped survival.
- Give two pieces of evidence that support the inherited claim.
- Give two pieces of evidence that challenge it.
