Search engines play an important role in the context of modern elections. By curating information in response to user queries, search engines influence how individuals are informed about election-related developments and perceive the media environment in which elections take place. It has particular implications for (perceived) polarization, especially if search engines' curation results in a skewed treatment of information sources based on their political leaning. Until now, however, it is unclear whether such a partisan gap emerges through information curation on search engines and what user- and system-side factors affect it. To address this shortcoming, we audit the two largest Western search engines, Google and Bing, prior to the 2024 US presidential elections and examine how these search engines' organic search results and additional interface elements represent election-related information depending on the queries' slant, user location, and time when the search was conducted. Our findings indicate that both search engines tend to prioritize left-leaning media sources, with the exact scope of search results' ideological slant varying between Democrat- and Republican-focused queries. We also observe limited effects of location- and time-based factors on organic search results, whereas results for additional interface elements were more volatile over time and specific US states. Together, our observations highlight that search engines' information curation actively mirrors the partisan divides present in the US media environments and has the potential to contribute to (perceived) polarization within these environments.

翻译：搜索引擎在现代选举语境中扮演着重要角色。通过策展信息以回应用户查询，搜索引擎影响着个体如何获知选举相关动态，以及如何感知选举发生的媒体环境。这对（感知上的）极化现象具有特殊意义，尤其是当搜索引擎的策展结果导致基于政治倾向的信息源呈现失衡时。然而，迄今为止，此类党派性差异是否通过搜索引擎的信息策展而产生，以及用户端与系统端因素如何影响该差异，尚不明确。为弥补这一不足，我们在2024年美国总统选举前对两大西方搜索引擎——Google与Bing——进行审计，考察这些搜索引擎的有机搜索结果及附加界面元素如何呈现选举相关信息，并分析其如何随查询倾向、用户地理位置及搜索执行时间而变化。研究发现表明，两大搜索引擎均倾向于优先展示左倾媒体信源，且搜索结果意识形态倾向的具体范围在偏向民主党与共和党的查询间存在差异。我们还观察到地理位置与时间因素对有机搜索结果的影响有限，而附加界面元素的搜索结果则随时间及美国具体州份呈现较高波动性。综合而言，我们的观察结果凸显出：搜索引擎的信息策展主动映射了美国媒体环境中存在的党派分歧，并有可能加剧该环境内的（感知性）极化。