Relationship therapist Megan Harrison, LMFT, argues that the silent treatment generally "is a means to attempt and inflict emotional suffering on someone as a result of sentiments of anger or irritation." They are subtly conveying that your acts and words are inappropriate by withholding approbation.
When someone is overwhelmed or furious and unable to explain oneself in a healthy way, they may choose the silent treatment. They may use the silent treatment to gain the upper hand by pressuring the other person to make amends or because they dislike conflict and don't want to engage in lengthy conversations. The silent treatment may be a learned tendency (perhaps because a parent employed it and they have no other options) or just a strategy they have tested and know works.
However, giving someone the silent treatment is a small-minded, passive-aggressive strategy used in emotional conflict. The silent treatment, often known as "stonewalling," is one of Dr. John Gottman's Four Horsemen, a group of characteristics that frequently indicate the end of a relationship since it violates every guideline of healthy communication.