The mobile environment of the 2020s is experiencing a vertical video revolution. The portrait, or vertical, screen format is replacing the traditional landscape, or horizontal, format to become the default for mobile video production and consumption. With the increasing use of vertical videos, an important, yet unanswered, question is how mobile users respond to this format. Therefore, we examine the effectiveness of mobile vertical versus horizontal video advertisements in terms of consumer interest, engagement, and processing fluency, as well as the underlying mechanism of the effort of watching the video ad on a smartphone in three studies. In a large-scale field study, we demonstrate that mobile vertical video ads increase consumer interest and engagement compared to horizontal video ads. In two experimental studies, we further show that mobile users process vertical video ads more fluently than horizontal video ads. Exploring the underlying mechanism for this effect, we find that mobile users experience less effort when watching a video ad vertically (vs. horizontally) on the smartphone in full-screen, as watching a vertical video does not require turning the phone. Importantly, we find that mobile users' age moderates this indirect effect, as younger mobile users (Generation Z) process mobile vertical video ads more fluently than older Generations X and Y. This article closes with implications for theory and suggestions for mobile marketers.

2020年代的移动环境正在经历垂直视频革命。纵向或垂直屏幕格式正在取代传统的横向或水平格式，成为移动视频生产和消费的默认格式。随着垂直视频的使用越来越多，一个重要但尚未解决的问题是移动用户如何响应这种格式。因此，在三项研究中，我们从消费者的兴趣，参与度和处理流畅性以及在智能手机上观看视频广告努力的潜在机制方面，研究了移动垂直视频广告与水平视频广告的有效性。在一项大规模的现场研究中，我们证明了与水平视频广告相比，移动垂直视频广告可以提高消费者的兴趣和参与度。在两项实验研究中 我们进一步证明，移动用户比水平视频广告更流畅地处理垂直视频广告。在探究这种效果的基本机制后，我们发现，移动用户在全屏智能手机上垂直（相对于水平）观看视频广告时，无需花费太多精力，因为观看垂直视频不需要转动手机。重要的是，我们发现，移动用户的年龄减轻了这种间接影响，因为年轻的移动用户（Z代）比X和Y一代的年长者更流畅地处理移动垂直视频广告。本文在结尾部分为移动营销人员提供了理论和建议。全屏显示在智能手机上），因为观看垂直视频不需要转动手机。重要的是，我们发现，移动用户的年龄减轻了这种间接影响，因为年轻的移动用户（Z代）比X和Y一代的年长者更流畅地处理移动垂直视频广告。本文在结尾部分为移动营销人员提供了理论和建议。全屏显示在智能手机上），因为观看垂直视频不需要转动手机。重要的是，我们发现，移动用户的年龄减轻了这种间接影响，因为年轻的移动用户（Z代）比X和Y一代的年长者更流畅地处理移动垂直视频广告。本文在结尾部分为移动营销人员提供了理论和建议。