It is quite typical for some people to improve their chances by undermining those of others. It is less burdening for one’s own mind than learning something completely new and becoming better that way, isn’t it? One way to distinguish some other from oneself is to ”fill the area” in that someone’s mind that is ”reserved” for something that he is about to become familiar with or might be interested about later in the future with rubbish.

Practically this requires that

• target person must actively deal with choosen subject in a way that creates new thoughts and connects with earlier ones and
• deal with the subject in a situation, which wouldn’t be suitable for learning it and
• something irritating would occur in that situation — which would lead to a possibility that later recall of related memories, concepts etc. would be harder, slower or even gross.

Because brain is normally rather plastic (neuroplastiticity) throughout the life, effects will not be permanent, but damage done might affect the navigability of target person’s life especially if effects are maintained by those others. It might also be laborious to reorganize one’s mind, if it comes to that.