Writing in 1900 in the Wiener Zeitung (Viennese Newspaper), Hans Gross (1847–1915), an Investigating Judge, Professor of Criminal Law at Czernowitz and editor of the Leipzig-based journal Archiv für Kriminal-Anthropologie und Kriminalistik (Archive for Criminal Anthropology and Criminalistics), complained of the narrow contemporary use of the term “criminal psychology.”¹ Under the auspices of criminal anthropologists, who had argued for the mental and, in some instances, physical distinctiveness of offenders, this term, Gross wrote, had come to refer exclusively to the peculiar psychology of the criminal.² Rejecting this a priori assumption of difference, Gross argued that the criminal’s psychology was not distinct from that of the non-criminal; the problems of perception, memory and testimony affecting the offender being identical to those that impacted on the other participants in criminal proceedings.³ With this in mind, Gross told his readers that the term “criminal psychology” should be used to refer, not to the study of the offender’s psychological difference, but rather to “all those lessons from general psychology, which for criminalists can be of importance in the consideration of the mental activity of criminals, witnesses, judges, expert witnesses and jurors – that is, all lessons of psychology that in a criminal trial can in any manner be useful.”⁴ These lessons, derived from extensive observation of individual psychology, would, Gross claimed, “…enable us to learn how we should handle and evaluate the claims of the accused, information from witnesses, the perceptions of judges, jurors and expert witnesses.”⁵ While Gross pointed to the 700 pages of observations he had collected in his 1898 book Criminalpsychologie (Criminal Psychology), he stressed that these were “…vanishingly few in comparison to those that we need.”⁶

While Gross sought to remobilise the term “criminal psychology,” in order to describe this new field, the discipline he envisaged in the pages of the Wiener Zeitung was to become more commonly known as forensic psychology. Dedicated to the psychology of all those involved in criminal proceedings, this new science promised to move away from an exclusive focus on the criminal to provide a holistic view of how human fallibility impacted upon criminal justice . While in Germany during the following decades a number of psychiatrists, psychologists and jurists took steps to realise Gross’ vision, by the inter-war period, it was apparent that, to a large extent, concentration on the criminal had simply given way to an equally narrow focus on the witness, particularly the juvenile witness . Writing in 1927, for example, the psychologist Paul Plaut (1894–1960) noted,

…the big questions, that for twenty years have occupied psychologists, centre nearly exclusively on the problems of the psychology of testimony. They got hold of the narrowest area of forensic psychology, in that, they specialised in the psychology of the witness and, also here, only again on a quite small, if not unimportant part, namely the psychology of children’s and juvenile’s testimony.⁷

Similarly, in the same year, the district court judge, Albert Hellwig (1880–1950) complained,

From the wide purview of forensic psychology is covered, nearly exclusively, the area of the psychology of the testimony of the witness, only slightly the psychology of the accused and as good as nothing on the very important psychology of interrogators, particularly of police officials and judges.⁸

While there were attempts, mainly on the part of jurists, to conduct investigations of the psychology of the judge and the jury and to develop a reliable psychological test to detect offenders’ lies, the psychological problems that arose from German criminal trials in the Imperial and inter-war periods acted far more as a stimulus for research on the witness than on any other participant in criminal proceedings.⁹ Figures like Plaut and Hellwig may have resisted this tendency, but it was the question of the credibility of the witness, particularly the young witness, that created a space for psychological expertise in German courtrooms. Coveted by the representatives of a range of disciplines, including psychiatry , psychology, forensic medicine and pedagogy, the role of psychological expert within criminal proceedings was highly contested in early twentieth-century Germany; arguments about competency coalescing around children’s testimony and trials, usually sex crimes trials, in which the statements of minors played a crucial part. Subtitled, Witnessing Crime, 1880–1939, this book, which traces the development of forensic psychology in Germany from the late nineteenth century through to the Second World War, is, therefore, largely a history of the psychology of the witness and the competing disciplines that claimed expertise in this area.

Emerging in the closing decades of the nineteenth century, concern about witness reliability was the result not only of new research within the mental sciences, which revealed the fallibility of perception and memory and the power of suggestion, but of legal reform, which had swept away those criteria that excluded witnesses on the basis of age, class or gender.¹⁰ Exploiting the growing anxiety around testimony for their clients’ benefit, professionalising German defence lawyers sought experts to testify to witnesses’ lack of reliability; in the late nineteenth century relying on psychiatrists with an interest in suggestion and in the early twentieth century mobilising psychologists and pedagogues who had conducted memory and testimony experiments.¹¹ Judges also, as the works of Gross and Hellwig demonstrate, were often intensely engaged in the psychology of testimony, in many cases claiming their own expertise, based on long professional experience, on witness credibility.¹² Beyond the courtroom, the press too were important in shaping forensic psychology in the German context, acting not simply as a means of communicating the findings of the psychology of testimony to the public, but as a key pressure group that provided impetus for judicial reform and expressed strong opinions on matters of witness reliability and psychological expertise.¹³ These opinions impacted upon the acceptance and success of forensic psychology in the lead up to the Second World War.

Multidisciplinary in both its conception and early development, forensic psychology, contrary to the short practitioner histories that constitute much of the historiography in this field, did not simply emerge at the fin de siècle, generated in the laboratories of psychologists determined to find real-world applications for their research.¹⁴ This is part of the story, of course, but tends to ignore the role of psychiatrists , Gerichtsärzte (forensic physicians) and jurists, which preceded the interest of psychologists in forensic questions and continued throughout the Imperial and inter-war periods, often in tension with psychologists’ claims to expertise. Nonetheless, the short works produced by practitioners such as Otto Undeutsch and Siegfried Ludwig Sporer are valuable in alerting us to the way in which the psychology of testimony evolved in the hands of psychologists such as William Stern (1871–1938), Karl Marbe (1869–1953) and Otto Lipmann (1880–1933); their experiments, courtroom appearances and campaigns for judicial reform were crucial to establishing the field in the early twentieth century and solidifying psychology’s monopoly over it following the Second World War.¹⁵ But, while Undeutsch and Sporer acknowledge the contributions of jurists like Gross and Franz von Liszt (1851–1919) to this nascent field, their narrow focus disguises both the heated cross-disciplinary debates around psychological expertise that characterised the Weimar period and the legal, financial and political contingencies, which prevented a clear winner in the “battle for forensic psychology” from emerging before 1939.

Building on practitioners’ brief explorations of the history of forensic psychology, a small number of doctoral these...