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New South Wales - Concept

Mental Deficiency (c. 1905 - c. 1960)

c. 1905
c. 1960
Alternative Names
  • Feeble-Mindedness

The term 'mental deficiency' was used in Australia from the beginning of the 20th century until the late 1960s and is often used in association with 'feeble-mindedness'. These terms were broad and included intellectual disability, social problems, criminality and even unconventional sexual behaviour, such as sex before marriage. It should not be assumed that people labelled 'mentally deficient' were intellectually or otherwise disabled - some 'mental defectives' were noted to be 'high grade', or of normal intelligence, but behaved in ways authorities could not accept.


'Mental deficiency' was an obsession for many medical experts, social reformers and psychologists. Some experts considered mental deficiency was inherited and sufferers should be institutionalised, while others argued specialist education could help. The head of the New South Wales State Children's Relief Department, Dr C.K. Mackellar, was a national authority on the subject and, after touring European, English and American institutions in 1912, wrote an influential report. His Department created a number of specialized institutions for 'mental defectives', including May Villa for boys and Brush Farm for girls, as well as cottages at Mittagong and Raymond Terrace.

The belief in 'mental deficiency' resulted in the abuse of the rights of many people who, if 'diagnosed' as mentally defective' could be institutionalised for lengthy periods. However, the idea that 'mental defectives' could be helped led to the development of special education, supported accommodation and other initiatives that were, at least, kinder than previous methods.

Related Concepts

  • Montessori Method (1910 - )

    Montessori methods were applied to the education of children classified as mentally deficient from 1915 onwards.

Related Organisations

Related Places



  • Ellmoos, Laila, Our Island home : a history of Peat Island, Department of Ageing, Disability & Home Care, Sydney, 2010. Details

Journal Articles

  • Evans, Caroline; Parry, Naomi, 'Vessels of progressivism? Tasmanian state girls and eugenics, 1900-1940', Australian Historical Studies, vol. 32, no. 117, 2001, pp. 322-333. Details

Online Resources

Sources used to compile this entry: Parry, Naomi, 'Such a longing': black and white children in welfare in New South Wales and Tasmania, 1880-1940, Department of History, University of New South Wales, 2007, 361 pp,

Prepared by: Naomi Parry