Final answer:
Most people go on the trip after booking a nonrefundable ticket due to loss aversion, as they wish to avoid the psychological pain of financial loss, which is significantly stronger than the pleasure from a gain.
Step-by-step explanation:
The reason most people would decide to go on the trip despite feeling sick and having booked a nonrefundable $400 ticket is due to a behavioral economic concept known as loss aversion. According to the renowned economists Daniel Kahneman and Amos Tversky, loss aversion means that we feel the pain of a loss approximately 2.25 times more than the pleasure of a gain. If you do not take the flight, you are acknowledging a financial loss, which typically feels more painful than the discomfort of traveling while not feeling well.
From a traditional economics standpoint, if you experienced a monetary loss equivalent to a financial gain, you would end up feeling neutral. However, behavioral economics research has shown that a loss is usually more impactful than a gain, leading people to make decisions that may seem irrational, such as taking a flight when sick, to avoid the feeling of losing money. This tendency can also significantly influence how people behave when investing, causing them to react more intensively to losses than to gains in the stock market.