Applying psychology to optimize product detail page design

According to psychology, a customer's purchasing decision will come from internal and external factors. Original: External Factors vs Internal Factors

In the given example, this is a product page, so the conversion goal here is definitely to add customers to the cart, this is the highest goal. Further explanation for you to visualize is that in the given example, there is an additional part to buy by pack, you can imagine it as up-sell for easy visualization, this is a secondary goal.

Now for the detailed analysis, there are some words that have to be in English for easier understanding.

Scarcity Principle
Element: Countdown Timer
Laws of UX: Goal-Gradient Effect
The effect is that the closer a user gets to achieving a goal, the more motivated they are to complete it. Countdowns create a sense of urgency, making users feel like they need to act quickly to achieve their goal of receiving a discount.

Social Proof
Element: Customer Reviews
Law of UX: Social Proof
Social proof is the principle that people follow the actions of others. Including testimonials with photos takes advantage of this principle by showing potential customers that others have used and benefited from the product, encouraging them to do the same.

Reciprocity Principle
Element: Discount Offer, 20% discount banner at the top of the page
The reciprocation principle is the social norm of responding to a positive action with another positive action. When someone does something good for us, we feel motivated to reciprocate. Offering a discount in the After version makes customers feel like they are receiving a special benefit. This can motivate them to reciprocate by making a purchase, feeling obligated to respond positively to the offer.

Commitment and Consistency Principle
Element: Pricing plans designed to be easier to understand
Law of UX: Hick's Law
Hick's Law states that the time it takes to make a decision increases with the number and complexity of choices. By presenting package options clearly, advertising simplifies the decision-making process, encouraging users to commit to a purchase.

Authority Principle
Element: Doctor trust badge
Law of UX: Authority Principle
The authority principle states that users are more likely to be influenced by authority figures. The doctor recommendation badge adds credibility, making users more likely to trust and purchase the product.

Contrast Principle
Law of UX: Von Restorff Effect The Von Restorff Effect, also known as the Isolation Effect, predicts that an item that stands out is more likely to be remembered. By contrasting before and after scenarios, highlighting the benefits of a product makes it more memorable and compelling.