The idea that worker utility is affected by co-worker wages has potentially broad labour market implications. In a month-long experiment with Indian manufacturing workers, in her work with Emily Breza and Yogita Shamdasani ([Breza et al. 2017](https://academic.oup.com/qje/advance-article-abstract/doi/10.1093/qje/qjx041/4430649?redirectedFrom=fulltext)) Supreet Kaur establishes the effects of pay inequality on co-workers within production units. They find that pay inequality reduces output, as well as attendance by 10%. Pay disparity also lowers co-workers' ability to cooperate. However, when workers can clearly observe productivity differences, pay inequality has no discernible effect on output, attendance, or group cohesion.