Over the past few decades income inequality in America has exploded, but there is considerable disagreement about the cause of the shift. Are impersonal forces like globalisation and technological development to blame, or is it to do with policies designed to disproportionately benefit the rich?

A recently published study by Tali Kristal, an Israeli sociologist, says that the overall share of income by the labour workforce is declining because workers are losing the power to fight for their own interests.

Ms Kristal found that the biggest inequality spikes have occurred within industries where unions have traditionally held a lot of influence – within manufacturing, transportation, and, to a lesser extent, construction. That’s partly due to the labour movement as a whole witnessing its power sharply declining since the mid-twentieth century, but Kristal has also identified another factor which she calls ‘class-biased technological change.’

Technological development is not apolitical or self-directed, she says. New tools are always made by human beings, and those humans have their own political influences and agendas. Institutions that fund technological development also tend to have a particular motive, whether it’s winning a war, curing a disease, or increasing corporate profits. Class-biased technological change simply means the sort of development which “favours capitalists and high-skilled workers while eroding most rank-and-file workers’ bargaining power”, according to Ms Kristal.

A good example of class-biased technological change is various kinds of factory automation, which can render some manufacturing jobs obsolete. But Kristal also highlights new workplace monitoring tools and increasingly sophisticated workplace control strategies, which have given managers unprecedented levels of power to use more legal and illegal anti-union tactics, such as the illegal discharge of union activists, surveillance of union leaders, captive-audience meetings with top management, and an entrenched refusal to negotiate collective agreements.

Tali Kristal does not mention Frederick Winslow Taylor in her paper, but his ghost haunts the margins. At the turn of the twentieth century, Taylor became one of history’s first professional management consultants, explicitly advising factory owners on how they could break the power of their employees’ craft unions. Nowadays, Americans tend to regard Taylor’s most influential innovations – such as the assembly line and the role of the middle manager – as benign improvements to efficiency. The assembly line, though, was designed in part to take control over the speed of production out of the hands of workers and into the hands of management.

If Kristal’s study is to be believed, Taylorism is alive and well in the United States. Fittingly, America is now experiencing levels of inequality last seen during the lifetime of its inventor.