Suffix effect
(rather than making remembering it optional).

Suffix effect is an important cognitive process that helps individuals remember words better. The process involves associating a meaningful word or phrase with a new word to form a meaningful relationship. For example, the suffix "ology" often appears at the end of related words such as biology, geology, sociology, and psychology. By making remembering suffixes mandatory, individuals will be more likely to remember related words, which results in better recall. Additionally, making the remembering of suffixes mandatory reinforces the cognitive process, which can make the task easier and more effective.