The ground covered by psychophysiology throughout the decades prior to its constitution as an independent discipline has not been well documented, despite its historical interest. A bibliometric study of the research published in scientific journals by 66 of the most relevant psychophysiologists from 1930 to 1964, analyzing the contents of the records indexed in the PsycINFO database, gives us an image of the state of the emergent discipline during that period. This study reveals that this was a period of consolidation, marked by the refinement of instruments and procedures, the characterization of measurements, and the establishment of the basic relationships between physiological and psychological variables, the development and validation of basic constructs such as activation, or interest in the study of psychopathology. In these years the foundations of psychophysiology were laid, leading to the formalization of the discipline at the end of the period.