Lisa Poole / AP file

Heavy bags are a real downer.

The charity workers staking out your favorite holiday shopping site with collection cups in hand may have chosen the exact right spot to prick your conscience, a new study suggests.  

It’s not that you feel guilty for your purchasing power.  It’s about the weight of your shopping bags.

Researchers found that when we are physically weighed down, with anything from groceries to gifts, our thoughts inescapably turn to serious -- weighty -- subjects.  Apparently, the wiring in our brain sparks directly from physical weight to psychological weight.

When we’re toting a big haul, we're more likely to be suddenly struck by the importance of current events or issues in the world around us, according to the report published in the Journal of Consumer Behavior.

“We found that carrying a heavy load leads consumers to feel an unrelated event as being more important and more stressful,” said the study’s lead author Meng Zhang, an assistant professor in the department of marketing at the Chinese University of Hong Kong.

For the new study Zhang ran a series of experiments on more than 100 people to look at the impact of heavy loads on thinking.

In her experiments, Zhang asked a group of volunteers to carry a shopping bag with bottles of water that weighed about 10 pounds. A comparison group carried bags with empty water bottles. The volunteers were told the experiment was to determine how much weight consumers might be willing to carry while shopping.

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Later, both groups were asked questions, such as how important it is for people to express their opinions in public, how important it was to read nutrition labels, or how important it was that people stay socially connected.

Sure enough, volunteers carrying the heavy bags tended to score higher on their answers to the societal questions. In other words, people carting around heavy bags were more likely to say lots of stuff was really important.

Perhaps even more intriguing was Zhang’s discovery that people could be nudged to think about the importance of weighty societal issues just by asking them to read narratives that included words such as “heavy,” “tons,” and “loaded.”

Is there an antidote to the psychological consequences of carrying a shopping bag loaded down with holiday loot?

Apparently there is.  In another experiment Zhang determined that the psychological impact of a heavy load could be diminished when people thought about lightweight objects, such as balloons and feathers.      

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