The «The Magical Number Seven» describes the very limited capacity of human short-term memory. This is biologically determined and cannot be increased by training. A person is thus able to retain 6 to 7 chunks of information in their memory for a short period of time after seeing them briefly once. A short-term memory that can store 8 objects would already be above average. In people with cognitive disabilities, it is short-term memory that is particularly affected – they can rarely remember more than 3 objects.
Origin
This insight was popularized by the work of psychologist George A. Miller, who published his studies in 1956 in the much-cited article "The Magical Number Seven: Limits on Our Capacity for Processing Information". This publication in the 'Psychological Review' is considered a milestone in cognitive psychology. In fact, however, it was John Locke who discovered the so-called 'seven phenomenon' over 300 years ago when he examined the comprehension of adults. He found that test subjects who saw a large number of objects for a brief moment and were then asked to remember them had a hit rate of almost 100% for up to seven objects. For more than seven objects, the hit rate dropped abruptly.
Application in UX and UI design
In particular, in connection with Hick's Law, according to which too many options slow down the decision-making process, it is clear that menus should never contain more than 6-8 entries per level. Thus, no grouping of information should consist of more than seven individual elements. This would be very important to keep in mind in the area of Chunking.
