According to research on cognitive dissonance theory, people betting on horses at the racetrack should feel after placing their bets than before placing their bets.

The answer is "more confident".

As per cognitive dissonance theory, there is a propensity for people to look for consistency among their comprehensions (i.e., convictions, conclusions). At the point when there is an irregularity between states of mind or practices (disharmony), something must change to dispose of the dissonance. On account of an inconsistency amongst states of mind and conduct, it is probably that the attitude will change to oblige the conduct.