WISENET Journal 35, July 1994, pp. 12-13.
by Margarita Bowen
Discoveries in brain evolution made by Lesley Rogers and colleagues in the last two decades are of enormous significance. They open exciting possibilities of bringing clear scientific evidence into the centuries-old debate on the classic dualisms of the old paradigm: man and nature, mind and body, inheritance and environment.
Moreover, they add weight to the current movement from anthropocentric to ecocentric views, and from linear to more holist forms of explanation. And they strike another blow, too, at some old myths about 'rational male' and 'emotional female' that have persisted in patriarchal societies since Aristotle's day.
After graduating from Adelaide University, Lesley spent several years at Harvard University's graduate school and at Tufts New England Medical Center Hospital, and completed her PhD at Sussex University on animal behaviour. Returning to Australia in 1972, she joined the University of New England in 1985, where she is now Professor and Head in the Department of Physiology.
In 1987 Lesley was awarded a Doctorate of Science from Sussex University - the first woman to be given this honour - for her research into brain development and behaviour, the field in which she has gained international standing.
During 1990 Lesley held a Visiting Professorship at the Center for Excellence in Psychology at Memphis State University, and continues to collaborate with leading researchers in the USA and UK, as well as in Australia.
In March this year she attended the first 'International Conference on the Orang-utan:The Neglected Ape', to report her research with Professor Gisela Kaplan on orang-utans in East Malaysia. That research will be published by the University of New England Press later this year under the title Orang-utans in Borneo.
Lesley has been President of the Australian Society for the Study of Animal Behaviour, and Australia's representative on the International Ethological Committee. She is also Associate Editor of the Asia Pacific Journal of Pharmacology. Currently President of the International Society of Comparative Psychology, she will head their next meeting in Brazil in July this year [1994].
An intriguing survey of Lesley's work is given in her 1993 Inaugural Public Lecture at the University of New England. As the following extracts show, its lengthy title, 'The evolution and development of brain asymmetry, and its relevance to language, tool use and consciousness', should not discourage the general reader from the gems it contains.
In that lecture Lesley explained her commitment to the study of neuroscience, or neurobiology, which developed as an independent discipline in the early 1970s to focus research on understanding the relationships between brain and behaviour, and is now growing rapidly, drawing on many fields including physiology, psychology and ethology.
'The brain is the most complex organ in the body, and it is the least well understood.'
Lesley's main interest is in asymmetry in brains - differences between the two hemispheres in function or structure. 'in most people language and speech production are primarily functions of the left hemisphere. This hemisphere controls the right side of the body, including the right hand and right side of the face. The right hemisphere controls the left side of the body'.
For a long time in Western science, as she notes, this characteristic 'was considered to be one aspect of the 'pinnacle' of evolution reached by humans, explaining our abilities in tool use and language. It also provided a possible basis for consciousness.'
Lesley is critical of attempts to use differences in brain asymmetry to explain a range of behaviour, from schizophrenia to sexual orientation. Early in her career she decided such simplistic conclusions needed exposure for their lack of convincing evidence.
'One of the earliest theories linking brain asymmetry to sex differences in behaviour suggested that, because women are more emotional than men, they must be more right-hemisphere dominant. This theory ignored the fact that women have superior verbal ability, and that this function is located in the left hemisphere. Another hypothesis, known as the Levy-Sperry hypothesis, argued that women have less lateralised brains than men, whereas yet another, proposed by Gray and Buffery in the early 1980s, claimed that women have more lateralised brains. The latter two hypotheses were based on ad hoc deductions made about sex differences in performance of spatial tasks.(1)
'Brain asymmetry is thus a scientific concept with broad ramifications into social attitudes.'
When her own studies in the 1970s of memory formation in the chick contradicted the prevailing teaching that the brain had evolved to form two equal halves, 'I realised then that I had made an observation that needed much further study if it was to stand against current scientific thinking.'
Since then Lesley has found not only functional but also some structural asymmetry in the chick brain. This, like the mounting evidence for tool use, handedness and language comprehension in a variety of animals, brings into question another assumption that has been basic to Western science.
'As all of these attributes were considered to be unique to the human species, a conceptual divide had been constructed between humans and other animals. If we had to evolve from monkeys and apes, at least we made a huge evolutionary leap away from them. Or, did we? My own work has shown that this is not the case for brain asymmetry. For tool use, too, humans are not unique.'
Following the work of Fernando Nottebohem, whose research with songbirds from 1970 to 1977 provided the first clear example of brain asymmetry in a nonhuman animal, Lesley and J.M.Anson in 1979 reported their discovery of asymmetry in the chicken brain by showing that the left and right eye record different visual information.(2)
Studies over the next decade indicated 'the similar functions performed by each hemisphere in chicks and humans'. They also supported an interactionist view of evolution.
'It is not possible to separate biological from environmental determinants (that is, genetic or hormonal influences from learning/ social influences).'
'As my laboratory has shown, learning itself can impose neurochemical asymmetries on the chicken brain.'
Evidence for the gradual evolution of language analysis and cognitive ability is also emerging. 'The recent upsurge of interest in animal consciousness has brought forth new information on the capabilities of even small brains, such as birds.'
'No longer can we simply say that a bigger brain is a better brain. Cognitive capacity depends on how a brain is wired up.'
Lesley believes the apparent inability of chimpanzees to communicate often merely reflects poor experimental design, and the laboratory conditions in which they have to live.
'I suggest that, if one day a chimp is given a chance to take up a chair like this, she may tell us some astonishing things! Our present knowledge should at least have led us to the conclusion that there is a continuum from animals to humans on the attributes once thought to be uniquely human.'
She again rejects simplistic explanations of complex behaviour. 'Genes or hormones do not act alone as biological determinants, but rather they interact with environmental factors to produce the unique pattern of brain organisation within the individual.'
Moreover, Lesley suggests that even in adulthood, brains can be modified by environmental stimulation.
'We now know that the brain is in dynamic interaction with its environment throughout life, and thus its pattern of asymmetry may shift in response to learning, stress factors or other forms of environmental input.'
These are questions on which she hopes her future research will shed some light.
Notes:
1 See L.J. Rogers 1988, 'Biology, the popular weapon: sex differences in cognitive function', in Crossing Boundaries: Feminisrns and the Critique of Knowledges, eds B Cain, E Grosz and M de Lepervanche, Sydney: Alien and Unwin.
2 An overview of these studies is given in J.L. Bradshaw and J.L. Rogers 1992 The Evolution of Lateral Asymmetries, Language, Tool Use and Intellect (San Diego: Acadernic Press).