Feeling sad and introspective, and think a little shopping might be the ideal therapy?
Don't do it.
According to a study released Friday at the annual meeting of the Society for Social and Personality Psychology, inward-looking people who are down in the dumps tend to spend more money on the same item than their neutral-emotion counterparts.
Earlier studies have drawn a link between mood and spending habits, but this one highlighted the key role played by how self-focussed a person is.
"It is the combination of sadness and self-focus that drives the effect, and it turns out that sadness leads to an increase in self-focus," said Cynthia Cryder, a doctoral student at Carnegie Mellon University and one of the co-authors of the study.
"What we think is going on is that sad and self-focussed people are feeling pretty bad about themselves and have a decreased valuation of themselves. They want to enhance this valuation, and one way to do this is by acquiring material goods," she said.
Placing a higher value on those goods could be an attempt by the sad, self-focussed person to boost their self-esteem by transferring the value of the item to themself.
The big problem is, the purchase is often regretted later.
"A huge key to avoiding decision-effects like this is being aware that you're sad in the first place. But that's rather hard to do," Cryder said.
"Participants in studies such as ours usually have no idea that their feelings influence their decisions, so it's impossible to correct," she said.
"Secondly, always re-evaluate major purchases one day or one week after you make them so that you can make sure that whatever you bought is still attractive to you," Cryder said.
"That lowers the probability that you'll have an over-priced mistake due to some fleeting influence that you didn't know about and still don't know about. You just know, 'Wow... why did I pay so much for that?'"