scientists and brain surgeons with evidence to support their selfassuredness in the company of the other party. We tested participants across several cognitive domains, including emotional discrimination and motor control. Instead of seeking an outright winner, we assessed 1 Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, UK 2 Cancer Institute, University College London, London, UK 3 Brainbook, London, UK 4 Department of Brain Sciences, Imperial College London, London, UK 5 Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK 6 Bristol Medical School, Faculty of Health Sciences, University of Bristol, Bristol, UK 7 Department of Neuroimaging, Kings College London, London, UK 8 Neurosciences Research Centre, Molecular and Clinical Sciences Institute, St George’s University of London, London, UK 9 Great Ormond Street Institute of Child Health, University College London, London, WC1N 3JH, UK 10Department of Neurosurgery, Great Ormond Street Hospital, London, UK Correspondence to: A Chari aswin.chari.18@ucl.ac.uk (or @aswinchari on Twitter ORCID 0000-0003-0053-147X) Additional material is published online only. 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Cite this as: BMJ 2021;375:e067883 http://dx.doi.org/10.1136/ bmj-2021-067883 Accepted: 8 November 2021 WHAT IS ALREADY KNOWN ON THIS TOPIC The phrases “It’s not rocket science” and “It’s not brain surgery” are commonly and interchangeably used for tasks or concepts that are easy Using such phrases suggests that both specialties are put on a pedestal of being difficult or requiring exceptional cognitive abilities Whether they are appropriate phrases and, if so, which of the two is more suitable have not been subject to scientific scrutiny WHAT THIS STUDY ADDS Aerospace engineers and neurosurgeons showed no difference in four of six validated cognitive domains; neurosurgeons showed better semantic problem solving abilities, whereas aerospace engineers showed better mental manipulation and attention abilities Most of the domain scores for both groups were within the range of those in the general population Both specialties might therefore be unnecessarily placed on a pedestal, and other phrases such as “It’s a walk in the park” might be more appropriate on 16 April 2022 by guest. Protected by copyright. http://www.bmj.com/ BMJ: first published as 10.1136/bmj-2021-067883 on 13 December 2021. Downloaded from CHRISTMAS 2021: WHAT IF . . . ? 2 doi: 10.1136/bmj-2021-067883 | BMJ 2021;375:e067883 | the bmj the cognitive characteristics of each specialty using a validated online test, the Great British Intelligence Test (GBIT) from the Cognitron platform. This test had been used to measure distinct aspects of human cognition, spanning planning and reasoning, working memory, attention, and emotion processing abilities in more than 250000 members of the British public as part of the GBIT project in association with BBC Two’s Horizon programme.8 The battery of tests should not be considered an IQ test in the classic sense, but instead is intended to differentiate the aspects of cognitive ability more finely. The large existing dataset also enabled us to benchmark both professions against the general population.9 The secondary aim of our study was to question whether public perceptions of rocket science and brain surgery are borne out in reality. Falling under the umbrella of science, technology, engineering, and mathematics (STEM) industries, neurosurgery and aerospace engineering face difficulties in maintaining their workforce and are predicted to be understaffed in coming decades.10 11 Considerable evidence suggests that school aged children’s desire to pursue a career is influenced by their perceptions of particular professions, in turn impacting on the diversity of the workforce and the trajectory of specialties.12 13 School aged children perceive STEM to be “masculine” and “clever.” This perception is heavily influenced by gender, class, and race, and deters females, people from lower socioeconomic groups, and people of non-white ethnicity from pursuing STEM careers.14 Perceptions and the stereotypes underlying them are derived from various sources, but school experiences and mass media are important.13 Questioning these stereotypes could have implications for public outreach and future recruitment. Methods We performed an international prospective comparative study, with participants recruited through the internet. Anyone who self-identified as an aerospace engineer or a neurosurgeon in the United Kingdom, Europe, the United States, and Canada was eligible to participate. The roles were defined as any individual who had completed a degree relating to the relevant specialty. As specialisation occurs at the postgraduate stage, we excluded individuals who were studying for their primary degree (undergraduate science or primary medical degree). This study was publicised via email and LinkedIn through our collaborators. The Society of British Neurological Surgeons and the Canadian Neurological Sciences Federation cascaded the invitation email to respective members. The UK Space Agency advertised the study on LinkedIn and through their partner organisations. The Royal Astronomical Society advertised the