MadSci Network: Neuroscience Query:

Both smiling and crying are known to be innate behaviours (ones that we are born with) that appear at certain stages in infant development. Newborn babies cry when they are uncomfortable and at around six weeks start smiling at anything and everything. This behaviour is then shaped by interaction with their parents or caregivers, for instance, after a while smiling occurs only with familiar people. Whilst a blind baby wouldn�t see people�s faces to smile at they would soon come to learn their sound and smell and smile at those.

Many other expressions such as eyebrow raising on recognising someone and frowning when puzzled appear to be universal amongst humans and therefor are probably innate. The only difference is that a blind person would recognise someone by sound or smell rather than by sight.

Certainly blind people don�t find it difficult to perceive other people�s emotions as our voices often signal how we are feeling. We rarely talk in monotone but bring in tones of voice, fillers like �er� or �um�, stress words differently and vary the speed at which we speak. They then react to the perceived emotion. For the deaf-blind this is a far greater problem but these days such children are taught more complex facial expressions by feeling theirs and others� faces at specialist schools and by using computer simulations.

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