Absolute Threshold

According to science, this is the lowest level of stimulus that humans will detect at least 50% of the time. What a wonderful body we live in that we are able to detect such small changes.

• hearing: the ticking of a watch 6 metres away in a quiet place
• smell: one drop of perfume in a large house
• taste: one teaspoon of sugar dissolved in 4 litres of water
• touch: the wing of a fly falling on the cheek from a height of one centimetre
• vision: the flame of a candle 50 kilometres away on a dark, clear night.

(Psychology by Lorelle J Burton, p 209, 5th Ed)