What is the origin of the unique and complex behaviours that our species are capable of? Is it nature or nurture? How is human cognition – our memory, language, numerical abilities – organised? How do developmental disorders occur? These age-old questions have puzzled – and deeply divided – scientists for hundreds of years. Over the course of more than four decades, research by the developmental neuroscientist Annette Karmiloff-Smith, who has died aged 78, provided key insights that challenged the traditional answers, and led to a new understanding of how genetic and environmental factors interact to give rise to different outcomes in individuals.
She argued that developmental disorders should not be understood as “normal minus something broken”, but as developmental trajectories that take very different paths from the typical. When one sees what appears to be the same behaviour in both typical and atypical populations, that behaviour may actually be supported by processes that are quite different in each population. Annette’s work in this area involved individuals with Down’s syndrome, Fragile X syndrome and Williams syndrome, among others.
Most recently, Annette moved into an area that appears at first to be an odd focus for a developmentalist – Alzheimer’s disease (AD). She pointed to an intriguing phenomenon: by later age, 100% of individuals with Down’s syndrome have brains that (on autopsy) have the signature characteristics of AD, even though not all of them have the cognitive deficits typical of this form of dementia. The question she asked is, what protective factor in these individuals inhibits the behavioural and cognitive effects that are otherwise associated with the brain characteristics of AD? At the time of her death, Annette was pursuing a set of hypotheses to address this question.
She began her career at the University of Geneva as a doctoral student in the mid-1970s under the developmental psychologist Jean Piaget, whose theories of development were dominant during most of the 20th century. While Annette respected those theories she was not afraid of challenging them.
The study of development at the time generally involved a “snapshot” approach, capturing infant and child behaviours at different ages. She believed the key to understanding development was to understand the mechanisms that underlie the trajectory of changes across developmental time that give rise to increasing complexity in behaviour. One of her early contributions was to pioneer the so-called “microgenetic” approach, which involved tracking developmental change at a fine grain of temporal analysis. The method has now become standard in the field.
Her early work was in the area of language development (prior to her studies, she had worked as a simultaneous French/English translator). This work brought her into contact with a wide range of scientists, including linguists, cognitive psychologists and developmentalists, who proposed that the human cognitive system was organised into modules innately present from birth. This proposal was hotly debated within all these fields.
Annette offered a fresh and compelling theory, which on the one hand did not require innate modules, but which on the other accounted for behaviours that seemed to implicate modular organisation. These ideas were the core of her book Beyond Modularity: A Developmental Perspective on Cognitive Science. Annette explained how modularisation – as a process – might result over the course of development as a result of internal cognitive changes that yielded successively more refined and more modularised knowledge representations (a process she called “representational redescription”). Thus, modularisation of knowledge need not be innate, but instead a result of learning and development.
In more recent years, Annette turned her attention to developmental disorders, both because of their public health importance and as potential windows into the mechanisms that underlie human cognitive development.
Born in London to Isaac Smith, a tailor, and Doris (nee Findlay), an administrator, Annette attended Edmonton County grammar school from 1949, and then the Institut Français, London (1954-57).
She loved languages, and so decided to work in Geneva as a UN translator; however this proved to be less intellectually stimulating than she had hoped. A chance encounter with Piaget in a bookstore led her to attend one of his courses, which she found fascinating, and she subsequently studied with him, gaining her BA in experimental psychology in 1970 and doctorate in 1977.
She then worked in Geneva and the Netherlands until 1985, and then moved to London, where she was a scientist at the Medical Research Council’s Cognitive Development Unit for 13 years. From 1998 to 2006 she was head of the Neurocognitive Development Unit at the UCL Institute of Child Health, and honorary research fellow at Great Ormond Street hospital. For the last 10 years, she was a professorial research fellow at the Centre for Brain and Cognitive Development, Birkbeck College, University of London.
A generous scientist, Annette mentored many students and inspired them with her zest for science. She was accessible, warm, funny and loyal and supportive to her many friends. She was also an excellent communicator, writing books for the general public such as Everything Your Baby Would Ask If Only He Or She Could Talk (1999), co-authored with her daughter Kyra, giving talks at festivals and appearing on shows such as The Life Scientific (BBC Radio 4).
Her first marriage, to the economist Igor Karmiloff, with whom she had Kyra and another daughter, Yara, ended in divorce. She subsequently married Mark Johnson, a cognitive neuroscientist, in 2001.
Annette was elected fellow of the Academia Europa (1991), British Academy (1993) and Academy of Medical Sciences (1999). In 2002 she received the European Latsis prize and an honorary degree from the University of Louvain. She was made CBE in 2004.
She is survived by Mark, Yara and Kyra, her brothers, Stephen, Peter, and Paul, and seven grandchildren.
• Annette Dionne Karmiloff-Smith, developmental neuroscientist,born 18 July 1938; died 19 December 2016