Abnormal market behavior where consumers purchase the higher-priced goods whereas similar low-priced (but not identical) substitutes are available. It is caused either by the belief that higher price means higher quality, or by the desire for conspicuous consumption (to be seen as buying an expensive, prestige item).
I wish to take exception at the less than precise and loaded wording of this quote from someone writing on Monash University official website. Just for the record, nothing more.
Delete the word abnormal and it becomes a close (but imperfect) explanation to what theoretical micro-economics may offer, where all manner of consumer preferences are carefully investigated. There is no judgement as to what is normal or abnormal.
There is truth in the words 'belief' and 'desire'. The motives are not so easily conveyed - that is psychology.