Developer communities increasingly rely on emoji reactions to communicate, but we know little about how these emotional signals spread and influence technical discussions. We analyzed 2,098 GitHub issues and pull requests across 50 popular repositories, examining patterns in 106,743 emoji reactions to understand emotional contagion in software development. Our findings reveal a surprisingly positive emotional landscape: 57.4% of discussions carry positive sentiment, with positive emotional cascades outnumbering negative ones 23:1. We identified five distinct patterns, with "instant enthusiasm" affecting 45.6% of items--nearly half receive immediate positive reinforcement. Statistical analysis confirms strong emotional contagion (r=0.679, p<0.001) with a massive effect size (d=2.393), suggesting that initial reactions powerfully shape discussion trajectories. These findings challenge assumptions about technical discourse being purely rational, demonstrating that even minimal emotional signals create measurable ripple effects. Our work provides empirical evidence that emoji reactions are not mere decoration but active forces shaping collaborative outcomes in software development.

翻译：开发者社区日益依赖表情符号反应进行交流，但我们对这些情绪信号如何传播并影响技术讨论知之甚少。我们分析了50个热门仓库中的2,098个GitHub议题和拉取请求，检查了106,743个表情符号反应的模式，以理解软件开发中的情绪传染现象。我们的研究结果揭示了一个令人惊讶的积极情绪景观：57.4%的讨论带有积极情绪，积极情绪级联的数量以23:1的比例远超消极情绪级联。我们识别出五种不同的模式，其中“即时热情”影响了45.6%的项目——近一半的项目获得了即时的积极强化。统计分析证实了强烈的情绪传染效应（r=0.679，p<0.001），且效应量巨大（d=2.393），表明初始反应有力地塑造了讨论轨迹。这些发现挑战了关于技术讨论纯粹理性的假设，证明了即使是最小的情绪信号也会产生可测量的涟漪效应。我们的工作提供了实证证据，表明表情符号反应不仅仅是装饰，而是塑造软件开发协作结果的积极力量。