Hopefully this will be helpful to those of you revising Moral Philosophy when considering Peter Singer:
A related position rests on the claim that what is good is desire satisfaction or the fulfillment of preferences; and what is bad is the frustration of desires or preferences. What is desired or preferred is usually not a sensation but is, rather, a state of affairs, such as having a friend or accomplishing a goal. If a person desires or prefers to have true friends and true accomplishments and not to be deluded, then hooking this person up to the experience machine need not maximize desire satisfaction. Utilitarians who adopt this theory of value can then claim that an agent morally ought to do an act if and only if that act maximizes desire satisfaction or preference fulfillment, regardless of whether the act causes sensations of pleasure. This position is usually described as preference utilitarianism.
Preference utilitarianism is often criticized on the grounds that some preferences are misinformed, crazy, horrendous, or trivial. I might prefer to drink the liquid in a glass because I think that it is beer, though it really is acid. Or I might prefer to die merely because I am clinically depressed. Or I might prefer to torture children. Or I might prefer to spend my life learning to write as small as possible. In all such cases, opponents of preference utilitarianism can deny that what I prefer is really good. Preference utilitarians can respond by limiting the preferences that make something good, such as by referring to informed desires that do not disappear after therapy (Brandt 1979). However, it is not clear that such qualifications can solve all of the problems for a preference theory of value without making the theory circular by depending on substantive assumptions about which preferences are for good things.
continue reading at http://plato.stanford.edu/entries/consequentialism/