Even though utility maximisation is ubiquitous in economic textbooks to model consumer behaviour, its usefulness is rarely demonstrated by evidence.
- Is there any evidence that some consumers do behave that way on at least some markets?
Utility maximisation applied to a representative agent is also often used to model the demand side of a whole market. However, here also, this is hardly ever justified by evidence. On the other hand, alternative models seem to have good properties too: for instance in Complex Economics by Alan Kirman, it is said that random consumption + heterogeneity of income suffices to construct an aggregate demand that decreases as price increases. Random consumption does not seem more stupid than perfectly informed utility-maximisation... but sounds definitely simpler.
- Is there evidence that utility maximisation used as a model of the demand side of a market is actually better than other (simpler) models of consumer behaviour?