Psychology is a crucial element in designing the right kind of systems, interfaces and experiences for your users/customers.
Anchoring bias has a huge impact on negotiations and the pricing of the products and influences how much the customer is willing to pay.
Focusing on only success stories results in “Survivorship Bias”. It distorts judgement and can lead to false conclusions because we tend to only focus on those who survived, overlooking those who did not. One of the most famous examples of this bias are the damaged World War II planes. The United States Armed Forces were supposed to put protective armour on their planes. They decided to examine the planes that returned home to check where was the most damage incurred. They noticed that the tail, wings, and body were riddled with bullets and decided to protect that area. But Abraham Wald observed that they were only protecting the damaged parts as observed in the planes that returned home and not the ones that did not. The damage was done on the ones that didn’t return, the one on the engine wasn’t factored in. Later, taking that into account, many lives were saved.
National Geographic conducted an experiment to demonstrate this effect: People mostly bought small popcorn when the only choices given to them were small ($3) and large ($7) sized popcorn. But, when a medium popcorn ($6.50), the “decoy”, was presented in the options, the large popcorn bucker started selling out in huge quantities. The subjects were led people to buy a costlier alternative than they would have otherwise.