My earliest publication was an undergraduate project in which I demonstrated that, contrary to Piaget's claims, three-year-old children were highly competent at judging quantities in different sizes and shapes of container if they were asked to share out juice/cakes 'fairly', instead of being asked ambiguous questions about which was 'more' or 'less' . My subsequent work for a doctorate in the Oxford Department of Psychology was influenced by Donald Broadbent and Anne Triesman. I studied coding and recoding of visual and verbal shapes, patterns and pictures and was particularly interested in questions about serial versus parallel processing.
At the post-doc stage, these interests led me on to study hemispheric asymmetry. This was the period when the specialization of the two hemispheres for different cognitive processes was being demonstrated by the first split-brain studies. My own research relied on presenting varying kinds of material to different visual fields, or different ears, and measuring response times. This showed that each hemisphere is specialized to carry out some of the component stages of a task like reading. One hemisphere has a leading role but does not operate in isolation. My research also showed that parallel processing of multiple items simultaneously is characteristic of the right hemisphere and serial processing item-by-item is the left hemisphere mode of operation. However, the technology for this work was extremely crude and was superseded by the new methodology of brain imaging which yields images of the brain functioning while performing specific tasks.
I had a change of direction and began studying cognitive ageing, looking at the effects of normal ageing (as opposed to pathological conditions such as strokes or dementia) and focusing especially on language and memory. Although this research was still within the experimental tradition it was supplemented by the use of questionnaires and self reports. Mental processing slows down with age so that, for example, speech comprehension is affected, especially when speech is rapid. Short-term memory capacity declines, affecting mental arithmetic and complex reasoning. I became fascinated by the marked problems that elderly people have in recalling proper names. This area of research does yield some useful practical applications especially since researchers moved away from a 'deficit model' emphasizing age-related decline and began to give importance to preserved or compensatory abilities.
My research on ageing broadened into several aspects of memory in everyday life including autobiographical memory and memory for knowledge acquired from formal education. A large-scale study of Open University students found that during the next 2-3 years people forgot much of what they had learned, but after that memory stabilized and about 30% of the original learning was retained. Another study of long term memory examined people's memory for their own medical history and revealed a startlingly poor recall. As a sort of finale to over 30 years of research in psychology I tried to bring a lot of threads together in an overview and critique of a large number of conceptual models of cognitive processes in which I asked the question — do these models really replicate the way the brain is organized? Or do they just reflect the way psychologists like to think about the brain? It seemed like a good question to end on!
Written by: Gillian Cohen