David Bloor will need little introduction to readers of this journal. A founding figure of the strong programme in the sociology of scientific knowledge, he shaped how a generation of scholars think about the social dimensions of science. In this new work, Bloor offers a meticulous study of pilot fatigue research conducted at the Cambridge Psychological Laboratory during and after the Second World War. The result is a book that sits comfortably alongside his earlier The Enigma of the Aerofoil (2011) in combining technical detail, archival depth and theoretical sophistication.

The story begins in 1940, when Frederic Bartlett and his gifted young colleague Kenneth Craik installed a decommissioned Spitfire cockpit in the Cambridge psychology laboratory. They modified their “Cambridge cockpit” into a sophisticated flight simulator to study how fatigue affected pilot performance during long sorties. Using real RAF pilots as test subjects, they ran a series of experiments with their novel apparatus that appeared to demonstrate significant fatigue effects on skilled action. Yet, as Bloor shows, this apparently straightforward conclusion concealed theoretical gambles, interpretive puzzles and an uncomfortable anomaly that would shape British experimental psychology for decades.

Bloor’s reconstruction of the Cambridge experiments is exemplary. Drawing on previously unexploited archival material, he argues that Bartlett interpreted his fatigue results through the framework of the Victorian neurologist John Hughlings Jackson, whose hierarchical model of the nervous system held that higher centers normally inhibit lower ones. Fatigue, Bartlett argued, affected not the execution of skilled actions but their timing: a claim about the locus of control within a complex system. This theoretical commitment shaped how the Cambridge group designed their experiments, collected their data, and interpreted their results.

The heart of the book is structured around a tension that emerged between the experimental findings and their practical relevance: what Bloor calls the ‘landing-accident anomaly’. This arose because, contrary to the laboratory findings that emphasized the important impact of fatigue, field data from Bomber Command on actual landing accidents appeared to show that fatigue effects were actually operationally negligible. This empirical inconsistency, which proved remarkably resistant to resolution both during and after the war, works as the book’s analytic hinge. It gives rise to what Bloor terms a series of ‘paradoxes’, wherein fatigue repeatedly behaved in ways that inverted the expectations that justified its study.

Bloor is less interested in resolving these tensions than in exploring how the scientists managed them – their efforts to preserve the credibility of their constructs in the face of empirical dissonance. Fatigue in this context becomes a negotiated product of experimental affordances and ideological commitments. He traces how the Cambridge group responded to the anomaly by reconceptualizing the relationship between laboratory conditions and real-world performance, treating the latter as a phenomenon that served to mask fatigue rather than contradict its effects. Readers familiar with the strong programme will recognize the architecture: causal symmetry, impartiality towards truth and error, and an insistence that explanation stop short of invoking epistemic virtue.

Subsequent chapters extend the argument by exploring parallel German and US approaches to studying fatigue. Bloor finds that these different groups approached the problem in distinct ways and reached varying conclusions that reflected their specific experimental traditions, theoretical commitments, and institutional arrangements. German researchers, coming from physiology and biomedicine, framed fatigue in terms of organic limits and studied it via centrifuges, altitude chambers and medical testing. The Americans, working within industrial psychology, framed it as a population-level management problem, to be studied via aggregate performance data rather than laboratory experiment. The pattern echoes that of Bloor’s earlier work on the aerofoil: national scientific cultures, with their distinctive relationships between theory and practice, producing divergent knowledge claims, even when confronting ostensibly the same phenomena.

Bloor writes with enviable clarity and patient exposition, even if the depth of detail can occasionally be daunting. The archival work is impressive: confidential wartime reports, unpublished memoranda and correspondence that casts new light on familiar figures. Historians of psychology will find much to value in the portraits of Bartlett, Craik and their postwar successors. Historians of science more broadly will appreciate how the case illuminates the relationship between controlled experiment and messy operational reality.

For STS scholars, the book raises interesting questions about interpretive flexibility in experimental practice. The cockpit itself functioned as a boundary object of sorts, mediating between aircraft engineering, laboratory experimentation, and simulated combat, while leaving the relation between cockpit performance and real combat flying persistently indeterminate. The landing-accident anomaly shows how field data can challenge laboratory findings without either simply winning or losing, and how controversies can generate new conceptual resources and research directions.

The book also offers a quiet meditation on the relation between theory and practice in wartime science. Bartlett and Craik were making theoretical bets about the workings of the nervous system, and the urgencies of war sharpened those bets without simplifying them. Operational pressure could not dissolve the burden of interpretation in this work, but it added gravity and immediacy to the choices it necessitated.

Kenneth Craik died in a cycling accident on the eve of VE Day, aged thirty-one. The Cambridge cockpit eventually ended up in the basement of a house owned by Bristol University, where it deteriorated beyond repair. Bloor’s book serves as a fitting memorial to both: a careful reconstruction of how scientists thought about human performance under demanding conditions, and a reminder that even controversial, anomaly-ridden research programmes can generate lasting intellectual resources. It deserves wide readership among historians of science, technology and medicine, and it confirms Bloor’s standing as one of the most rigorous and readable scholars in the field.