This article analyses the initiating role of the steel industry in educational selection by means of psychometric techniques used in the psycho-physiological laboratory associated with a vocational school in Luxembourg founded in 1914. It first considers the origins of, and initial meanings bestowed upon, this first (and perhaps also last) Luxembourg Laboratory of Psychophysiology. Second, it investigates whether and, if so, to what extent psychometric techniques developed in this laboratory for vocational orientation were used strategically to foster an ethic of individual harmony by means of objectified observation and categorisation of the aptitude. What hidden agendas underpinned the industry's rhetoric regarding the rebirth of the individual and the empowerment of personal vocation through science-oriented processes like quantification, measurement and rational assessment? Did such rhetoric legitimise the industry's self-image as a privileged force in structuring the social fabric as well as individual lives?