When, on a particular shopping trip, a consumer purchases an item which he previously had no intention of purchasing, this sale is called an impulse purchase   The objects of impulse purchases are occasionally essential items (i  e  items that satisfy basic subsistence needs), but much more frequently are luxury or non-essential items
Researchers have determined that, at the end of a shopping trip, a consumer is much more excited if she has bought a luxury item on an impulse purchase, than if she had made no impulse purchases
The researchers had a reliable way to determine whether the consumer had planned to buy the luxury or non-essential item he purchased on that trip.