A Christmas lesson: How a single splurge can trigger a shopping spree

“If you’re going to go out and shop for something and you see it has a unique design, maybe you should stop and think whether or not this fits with what you already have at home,” said Henrik Hagtvedt, a marketing professor at Boston College. “If it doesn’t, the price might be a lot larger than what you actually purchased.”

“You might end up buying things to match this for God knows how long,” he added. “It could lead to a virtually never-ending process of just buying more.”

That cycle of spending is familiar to many, Hagtvedt said.

The 18th-century French philosopher Denis Diderot, for one, wrote an essay about an elegant red dressing gown that he had received as a gift. As soon as Diderot put the garment on, his study looked scruffy to him in comparison, which led him to redecorate the entire thing, with new drapes, furniture, a clock and more. By the end of the essay, the philosopher realized that one beautiful object had both depleted his finances and made him deeply unhappy.