Subjectively, getting more sleep seems to provide big benefits: Many people find it gives them increased energy, emotional control, and an improved sense of well-being. But a new study co-authored by MIT economists complicates this picture, suggesting that more sleep, by itself, isn’t necessarily sufficient to bring about those kinds of appealing improvements. The study is based on a distinctive field experiment of low-income workers in Chennai, India, where the researchers studied residents at home during their normal everyday routines — and managed to increase participants’ sleep by about half…