The Rule of Seven was described by the cognitive psychologist George A. Miller. Miller argued that …
- The number of objects an average human can hold in working memory is 7 ± 2. This is also referred to as Miller’s Law.
- The capacity of human short term memory is genetically determined and cannot be increased by any type of training.
Therefore, in order to anchor vocabulary efficiently in your long-term memory, you should limit yourself to learning 7 (seven) words or phrases a day.
For more, see— http://en.wikipedia.org/wiki/Rule_of_seven