Which of the following is an attitude-change strategy focused on already held beliefs?

The focus of the question is on attitude-change strategies that specifically pertain to beliefs that consumers already hold. The selection that emphasizes enhancing existing positive beliefs is indeed the most aligned with this concept.

By increasing the strength of existing positive beliefs, marketers reinforce the favorable views and associations that consumers already have. This strategy is beneficial because it builds on the foundation of consumer trust and satisfaction that has already been established. When consumers have strong, positive beliefs about a product or brand, they are more likely to remain loyal and advocate for it. Such reinforcement can be accomplished through various marketing techniques, such as emphasizing testimonials, sharing success stories, or providing evidence that corroborates those pre-existing beliefs.

This approach contrasts with the other options. While adding new positive beliefs attempts to introduce additional favorable thoughts, it does not focus on the strength or existing nature of the beliefs. Removing negative beliefs aims to eliminate any unfavorable perceptions rather than bolster positive ones. Finally, introducing competitor comparisons focuses on positioning the product in relation to others, which shifts the focus from existing beliefs to comparative assessments rather than strengthening them. Thus, enhancing the strength of already-held positive beliefs provides a targeted and effective means of changing attitudes without the need for introducing new information or shifting focus.