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Advertising is central to e-commerce. In a world of choice, ads drive consumption by informing consumers about available products. New insights into the influence of online advertising on e-shopping behavior come from a study led by Ralf van der Lans of HKUST. The team used eye-tracking experiments to probe how ad features and site design can help or hinder planned purchases.

Online advertising is big business. A 2020 report estimated its yearly value to U.S. firms as $125 billion—not surprising, given the ubiquity of Internet-enabled devices. Data on clicks and purchases tell us which online ads work, but not how. To tap the full potential of online advertising, say the authors, “process insight is crucial in understanding and shaping consumers’ decisions to click.” This motivated a suite of novel and rigorous experiments involving volunteers.

Ad-driven shopping is not always spontaneous. Apart from triggering new purchase intentions, ads guide us in searching for specific products we have already decided to buy. However, studies have generally failed to consider how advertising influences the implementation as opposed to the formulation of intentions. Van der Lans’s team proposed that the pictorial details of online ads (e.g., product photos or brand logos) and the visual layout of platforms determine how quickly shoppers can find a product.

Online shoppers typically make purchase decisions soon after seeing an ad. To capture this in the lab and investigate the visual processing of ads, the team performed three eye-tracking experiments, measuring where consumers’ gazes fell. In each experiment, volunteers first viewed an ad for a product—e.g., a pair of shoes—and then searched for that product on an online platform where alternative makes and brands were available.

The first experiment showed that ads increased the product search speed only if they included a photo of the target product—brand logos alone did not help. Eye-tracking analysis revealed that shoppers who had seen a product image looked at rivals on the platform less often and were less distracted by rival products’ color features, explaining their speedier target search. This overturns conventional intuition. “The majority of consumers believe that online ads do not help them find the product they are searching for,” report the researchers, “and that even if ads help, the design of the shopping website plays no role.”

The next eye-tracking experiments confirmed that online ads must show product images and yielded two further findings. First, the main effect was time-limited—participants who performed multiple search tasks between seeing the ad and locating the target did not benefit, speed-wise, from ad exposure. Second, the “image effect” worked whether products were arranged randomly, alphabetically, or by visual features. This effect was most prominent on disorganized platforms.

These results were confirmed in follow-up experiments that did not include eye-tracking but involved a realistic, participant-driven search process. Drawing on these findings, online retailers will benefit from knowing that clear, colorful photos help consumers disregard competition while making planned purchases—especially when the target products appear on visually cluttered platforms.