We executed 24,000 search queries in 243 countries, generating 2.8 million AI and traditional search results in 2024 and 2025. We found a rapid global expansion of AI search and key trends that reflect important, previously hidden, policy decisions by AI companies that impact human exposure to AI search worldwide. From 2024 to 2025, overall exposure to Google AI Overviews (AIO) expanded from 7 to 229 countries, with surprising exclusions like France, Turkey, China and Cuba, which do not receive AI search results, even today. While only 1% of Covid search queries were answered by AI in 2024, over 66% of Covid queries were answered by AI in 2025 -- a 5600% increase signaling a clear policy shift on this critical health topic. Our results also show AI search surfaces significantly fewer long tail information sources, lower response variety, and significantly more low credibility and right- and center-leaning information sources, compared to traditional search, impacting the economic incentives to produce new information, market concentration in information production, and human judgment and decision-making at scale. The social and economic implications of these rapid changes in our information ecosystem necessitate a global debate about corporate and governmental policy related to AI search.

翻译：我们在243个国家执行了24,000次搜索查询，于2024年和2025年共生成280万条人工智能与传统搜索结果。研究发现，人工智能搜索在全球范围内迅速扩张，并呈现出关键趋势，这些趋势反映了人工智能公司此前隐藏的重要政策决策，这些决策影响着全球人类接触人工智能搜索的程度。从2024年到2025年，接触谷歌AI概览（AIO）的国家总数从7个增至229个，但存在令人惊讶的例外，如法国、土耳其、中国和古巴，这些国家至今仍未获得人工智能搜索结果。2024年，仅有1%的新冠疫情相关搜索查询由人工智能回答，而到2025年，超过66%的新冠疫情查询由人工智能回答——这一5600%的增长标志着在这一关键健康议题上明确的政策转变。我们的研究结果还表明，与传统搜索相比，人工智能搜索呈现的长尾信息源显著更少，回答多样性更低，且低可信度信息源以及右倾和中间倾向信息源显著更多，这影响了生产新信息的经济激励、信息生产领域的市场集中度，以及规模化的人类判断与决策。信息生态系统中这些快速变化所带来的社会与经济影响，亟需引发一场关于人工智能搜索相关企业与政府政策的全球性辩论。