Absolute Thresholds


Absolute threshold is the minimum amount of light, sound, pressure, or other physical energy we, as humans, can detect.

Human Sense
Absolute Threshold is Equivalent to:
A candle flame seen at 48.27 km on a clear night
The tick of a watch under quiet conditions at 6.096 m
5 mL of sugar in 7.56 L of water
1 drop of perfume diffused into the entire volume of air in a 6-room apartment
The wind of a fly falling on your cheek from a distance of 1 cm

(Bernstein, Cramer, Fenwork, & Frasee, 2008).

‚Äč However, the absolute threshold is not an entirely accurate method of approach since on occasion the faint stimulus may be perceived in one given situation and entirely missed in another. With that said, psychologists have taken the 50% approach; being the lowest stimuli perceived 50% of the time. As well, psychologists took note of how different two stimulus' need to be in order to be perceived as different. This is known as the just noticeable difference (JND), the minimum difference in stimulation detected 50% of the time. (Psychology Glossary, 2010). A great example of this is if one was to have sand on their hand and someone was to continually add sand until the individual could note the overall weight difference. At that point that difference between the initial and the final weight would be known as the JND. (Psychology Glossary, 2010)