Indeed, advertising and marketing significantly influence consumer behavior and shopping decisions, integrating elements of psychology to be more effective. Below are common ways how they impact shopping psychology:

**1. The Power of Influence:**

Marketers use social proof in their messaging to convince prospective customers that their product or service is popular or endorsed by trustworthy figures or peers. 

**2. Scarcity & Urgency:**

Products marketed as limited edition or time-bound offers create an urgency to buy, triggering the fear of missing out. 

**3. Emotional Appeal:**

Advertising often appeals to emotions. Ads that evoke strong emotions (happiness, astonishment, nostalgia, etc.) tend to be more memorable and impactful, encouraging consumers to buy.

**4. Use of Colors:**

Colors have psychological effects. For instance, red may create a sense of urgency, blue a sense of trust and security, green may evoke peaceful feelings, and yellow grabs attention and evokes positivity.

**5. Repetition:**

Seeing an ad repeatedly helps with brand recognition. The more familiar people are with a brand, the more likely they will consider it while shopping.

**6. Reward & Loyalty Systems:**

Loyalty programs, rewards, discounts, and other incentives encourage repeat purchases, fostering customer loyalty.

**7. Personalization:**

Personalized advertising based on customer preferences and browsing habits make the customer feel valued and increases the likelihood of a purchase.

**8. Decoy Effect:**

Often seen in pricing strategies, the decoy effect involves offering three options(with one option notably worse) to make the more expensive option look more attractive.

**9. Anchoring Bias:**

This is when the first price a customer sees (the "anchor") significantly impacts their judgment of subsequent prices.

Keep in mind these are psychological tactics used by marketers and advertisers to shape consumers' perceptions and buying behaviors subtly. As consumers, understanding these can help us make more informed shopping decisions.

Social proof is a powerful tool that marketers use to validate the goodness or popularity of a product or service. The core of social proof lies in the psychological tendency of humans to conform or to follow the majority. Here's how marketers typically use social proof in their advertising messages:

**1. Customer Reviews and Ratings:** The most common form of social proof is user reviews and ratings. Positive evaluations by others affirm the quality of a product or service. These are often depicted on product pages, websites, or other advertising mediums to demonstrate customer satisfaction.

**2. Testimonials:** These are more formal, positive reviews given by customers, often highlighting how a product or service helped them. Seeing genuine experiences can significantly influence potential customers' decisions.

**3. Celebrity Endorsements:** When a celebrity or an influencer promotes or endorses a product, it tells their audience (who often admires or trusts them) that the product is good. This boosts the product's perceived value and appeal.

**4. Influencer Recommendations:** It's similar to celebrity endorsements, but on a smaller scale. Influencers, especially in niche fields, have a loyal followers base that values their recommendations, thus serving as an effective form of social proof.

**5. Case Studies:** These comprehensive overviews of real-life client experiences describe how a company's product or service solved a problem, demonstrating proven results.

**6.   As seen in   Mentions:** Brands often highlight if their product or service has been featured or mentioned positively by a reputable media source. 

**7. User numbers or Statistics:** Companies might highlight the number of users/customers they have or other engagement statistics to show widespread use and enjoyment of their products or services.

**8. Certifications and Badges:** These show recognition from authoritative bodies in the company's industry, adding credibility to the product or service.

**9. Social Media Activity:** Shares, likes, comments, and followers on social media platforms are other forms of social proof, showing that others interact with and approve of the brand or product.

Essentially, social proof leverages the notion of "following the crowd" to encourage more people to try a product or service. It is important to ensure that all social proof used in marketing is authentic and genuine to maintain customer trust and loyalty.