executive functions are often invoked when it is necessary to override prepotent responses that might otherwise be automatically triggered by stimuli in the environment. for example, on being presented with a potentially rewarding stimulus, such as a tasty piece of chocolate cake, a person might have the automatic response to take a bite. however, where such behavior conflicts with internal plans (such as having decided not to eat chocolate cake while on a diet), the executive functions might be engaged to inhibit that response.