Cognitive pruning involves the process of eliminating unnecessary clutter from and allowing more important aspects to fill in the gaps into the cognitive field of a learner (Brown, 1972). Very interestingly, some of the small aspects learned already gradually lose their value and identity in their own right and become subsumed into a single larger aspect or structure. These small aspects are thus pruned out and the larger aspect assumes the role of all the small aspects combined together.
In the beginning stages of learning a language, based on teaching/learning approaches, learners are encouraged to study some definitions, such as parts of speech in grammar, rules, such as changing verbs into progressive forms with the addition of +ing, and certain greetings, such as good morning/hello/hay. These things facilitate subsumption and learners at a later stage are able to converse on a particular topic, say ‘Having a conversation with a friend about attending a marriage ceremony’ in the target language. When learners become able to converse easily on certain topics in the target language, the greetings learned earlier individually are gradually pruned out and the conversation as a whole becomes a larger and more important aspect. Though learning greetings is a meaningful learning in the beginning, forgetting intentionally takes place. Now, learners do not have to learn greetings individually as it becomes unnecessary and as they have better achieved the goal of communicative competence.
When teachers find that learners are making progress in learning a language, they might tend to prune out unnecessary, small things being practiced individually by their learners by directly asking learners to remove certain aspects of what they have already learned and to become more specific. Sometimes even learners themselves naturally, in the process of conversation, ignore such less important or sometimes unnecessary aspects already learned and make their language learning a better experience.