The school of thought that would most likely agree with uncle John is behaviorism.
Behaviorists believed that every type of action and behavior should be observed so as to be researched. If it cannot be directly observed, it doesn't require particular attention because it is not as relevant. Some famous behaviorists are Skinner, Watson, Pavlov, etc.
Answer: The technique that is used to sell to customers and persuade customers is called low ball
When marketing your product psychological tactics can be used to persuade customers through understanding their behaviour.
There are so many ways to psychological convince your customers to buy your products for example when you are selling health food there are ways that you can manipulate people's mind for example showing them pictures of how unhealthy eating affect the person's body; by seeing those pictures a mind will tell the person to change their behaviour so that they will not look that way.
Knowing how the person brain works in making a decision to buy can help a business owner make the right decisions to persuade their customers appropriately.
"Cry in the dojo, laugh on the battlefield."
