The BPS Research Digest has a wonderfully straightforward explanation of a branch of psychology called psychophysics, which attempts to understand the relation between physical qualities and the psychological impressions they cause.
The piece is written by Mind Hacks co-founder and psychophysicist extraordinaire, Dr Tom Stafford, who explains how this key area of psychology uses mathematical models to understand how the brain makes sense of the physical world.
Tom explains how psychophysics tackles these sorts of problems and then explains one of the most important discoveries in psychophysics: Weber’s law.
Psychophysics is heavily used in ergonomics and human-computer interaction.
Knowing, for example, how noticeable something is (like a warning light), gives a huge advantage when trying to design safe and easy-to-use software interfaces, jet fighter cockpits or even home appliances.
Link to BPSRD article ‘An introduction to psychophysics’.