It happens all the time on the plane. Two people get to talking and, soon enough, one discovers he paid a lot more than his in-flight neighbor for the ticket. Now, new research from a pair of Brandeis University economists suggests shoppers at the Fulton Fish Market might want to make small talk as they wait in line.

Kathryn Graddy and George Hall, both at Brandeis’ International Business School, studied fish-purchasing patterns over 22 weeks and found that white customers usually pay five cents, and sometimes up to 10 cents, more than their Asian counterparts when buying a pound of whiting at the Fulton Fish Market in New York City.

Whenever a buyer approaches a fish stand, the economists write, a fish dealer’s expert eye scans “his type” and evaluates his price elasticity. As a rule of thumb, Asian customers mean tougher haggling and lower prices; their white counterparts are a quicker sell, yielding higher profits for the vendor.

Whiting bought by Asians, in fact, mostly ends up in fish sandwiches and fish balls in low-end fry shops where retailers have little scope to pass higher prices onto frugal customers. White buyers tend to represent more upscale restaurants or shops where they can pass on the price difference to the consumer. They also want to get out fast — and can afford to do so.

White shoppers would fare better in a fish market with fixed and publicly displayed prices, Graddy and Hall conclude. Here “the inelastic white customers pay lower prices, purchase larger quantities of fish, and make more frequent purchases.” On the flip side, the more elastic Asian buyers would end up paying more and buying less.

So how could New York’s fish shoppers be in the dark for so long over this? Easy, the report says, they rarely mix with each other.