This raises the question: How do users behave when they know about the presence of ads, and how does their behavior differ from that of users who are unaware of ads? In our study, we addressed whether user knowledge of ads correlates with specific types of search behavior.

The study comprised two parts. In the first, we asked users to work on different search tasks to determine their search behavior on results pages containing ads. In the second part, participants filled out a questionnaire to determine how knowledgeable they were about ads. In total, 100 people participated in the study.

Participants were given simple search tasks in part one such as: “Imagine you want to build a desktop computer yourself. A Google search returned the following results. Please click on a result.” The study did not focus on task completion but rather how the participants interacted with the search engine results page. As subjects worked on the task, their click behavior (which results they selected) and gaze behavior (how intensely they directed their gaze at individual search results) were recorded. The gaze was followed with the help of eye trackers.

Eye trackers use infrared technology to determine which part of a screen—for example, a Google result page—a person is currently looking at. Heat maps can then visualize which areas were viewed and for how long. The greater the intensity of viewing, the “hotter” (redder) the heat map is at that spot. The following figure shows a section of a heat map from a results page used in the study. At the top of the page, you can see five illustrated shopping ads and one text ad. The organic (non-paid) results appear below the ads. The colors displayed here indicate the shopping and text ads at the top were viewed with great intensity, as was the first organic result. The other organic results appearing further down received less attention.

In the second part of the study, we used a questionnaire to determine how much knowledge about Google ads participants possessed. For instance, one of the questions was “How does Google generate revenue?” Depending on how many of the questions were answered correctly, each participant received a score ranging from 0 (all answers incorrect) to 100 (all answers correct). After conducting the study, we took the results of selection behavior, gaze behavior, and ad knowledge and analyzed them for correlations.

The results of the study show that ads were viewed intensely by users, regardless of whether they were familiar with ads or not. The main reason for the high visual attention on ads is their prominent placement as described above. Or, in other words, it is nearly impossible to not look at the ads. Even if a user wants to scroll down directly to the organic results, ads come into view first. However, ad knowledge played a crucial role in selection behavior. Users with little knowledge of ads were more likely to click on an ad than users who knew these ads exist. This indicates that advertising-unaware users chose results without realizing that they were clicking on paid advertisements.

Why is this problematic? When users treat all search results as if they were organic, they cannot take into consideration the motivations behind the advertising, which are usually commercial in nature. Yet being a digitally empowered citizen demands an awareness of these influences. Thus, there is a need for information literacy training that allows users to select more appropriate results, for instance by enabling them to distinguish between ads and organic results. Furthermore, companies that operate search engines should label their ads in such a way that users actually perceive them as ads.

The study, a translation of the JASIST article “How users’ knowledge of advertisements influences their viewing and selection behavior in search engines,” is freely available (open access) at https://dx.doi.org/10.1002/asi.24410