Robot arms weld a vehicle at the General Motors plant in Lansing, Michigan. Automakers are the biggest users of industrial robots, which have decreased employment and wages in local economies. Who is winning the race for jobs between robots and humans? Last year, two leading economists described a future in which humans come out ahead. But now they’ve declared a different winner: the robots. The industry most affected by automation is manufacturing. For every robot per thousand workers, up to six workers lost their jobs and wages fell by as much as three-fourths of a percent, according to a new paper by the economists, Daron Acemoglu of M.I.T. and Pascual Restrepo of Boston University. It appears to be the first study to quantify large, direct, negative effects of robots. The paper is all the more significant because the researchers, whose work is highly regarded in their field, had been more sanguine about the effect of technology on jobs. In a paper last year, they said it was likely that increased automation would create new, better jobs, so employment and wages would eventually return to their previous levels. Just as cranes replaced dockworkers but created related jobs for engineers and financiers, the theory goes, new technology has created new jobs for software developers and data analysts.