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VIENNA — When a potential buyer makes an offer on eBay, sellers face a simple choice: accept, reject, or counter. New research reveals that the time taken to make this decision could significantly influence the outcome of the deal.

According to an international team of researchers, including scientists from Ohio State University and UCLA, the study shows that both buyers and sellers take significantly longer to accept unfavorable offers and reject favorable ones. This response time pattern inadvertently reveals private information about how close an offer is to someone’s target price.

“The finding adds a new element to game theory—the scientific study of strategic interactions—by considering not just what people choose, but how quickly they choose it,” explains corresponding author and UCLA psychology professor Ian Krajbich, in a statement.

The study, published in the Proceedings of the National Academy of Sciences, analyzed millions of real-world bargaining interactions on eBay. Researchers examined how people make decisions when they have private information they’d prefer to keep hidden. While traditional economic theory assumes people have preplanned strategies for every situation, the paper suggests most people actually make decisions in the moment.

On eBay, sellers can list items at a fixed price while allowing buyers to make offers. After receiving an offer, sellers can accept, reject, or counter. If rejected, buyers can make another offer, and negotiations continue until they agree on a price or someone walks away. Buyers also have the option to end negotiations by purchasing the item immediately at the listed price.

The results revealed clear patterns in response times. When receiving an offer worth 90% of their asking price, sellers typically responded within 48 minutes. However, when the offer was only 20% of their asking price, they took nearly two hours to respond with an acceptance. For rejections, sellers took about 78 minutes to reject low offers but close to two hours to reject relatively good ones.

“Take a slow response as a good sign rather than a bad sign,” advises Krajbich. “Don’t get discouraged. Don’t think that the seller is lazy or just dragging you along. Instead, consider that you might have them on the hook.”

Experience plays a significant role in decision-making speed. More experienced sellers responded more quickly and were more willing to accept offers, suggesting that professional sellers approach transactions more efficiently and with less emotional attachment to their items.

One unexpected finding contradicted economic theory. “What’s maybe most surprising in these results is that buyers don’t seem to be using this information as strategically as they should,” notes Krajbich. While slow rejections typically indicate a seller is close to accepting an offer, buyers often misread these signals. “In fact, buyers were more likely to make second offers to sellers who had slapped them down quickly,” he adds.

The researchers used computational models called drift-diffusion models to analyze these decision patterns. These models, which track how people gather evidence before making choices, showed that response times followed predictable patterns based on how close offers were to sellers’ target prices.

Lead author Miruna Cotet, a postdoctoral scholar at Complexity Science Hub Vienna, investigated several possible explanations for why buyers retreat from slow-responding sellers. The team considered whether buyers were switching to other sellers, buying items at full price, or losing interest in impulse purchases. However, none of these explanations fully explained the behavior.

The study delivers clear strategic insights for marketplace participants: sellers may inadvertently drive away potential buyers by responding slowly, while buyers might miss out on good deals by misinterpreting slow responses as negative signals. Perhaps now you’ll think twice next time you’re trying to haggle with your favorite eBay store owner.