When you raise taxes on the highest earners, you are essentially asking them to pay more money to the government. This can have a number of different effects, depending on the specific tax and the specific person.
Generally, raising taxes on the wealthy can lead to a decrease in their overall spending. This can then have a ripple effect throughout the economy, as the wealthy tend to be some of the biggest consumers.
It can also lead to an increase in underground economies, as people look for ways to avoid paying higher taxes.
Finally, it can lead to a brain drain, as the most talented and ambitious people may leave a high-tax area in search of better opportunities elsewhere.