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Professor Lesley Rogers was interviewed in 2001 for the Interviews with Australian scientists series. By viewing the interviews in this series, or reading the transcripts and extracts, your students can begin to appreciate Australia's contribution to the growth of scientific knowledge.
The following summary of Rogers’ career sets the context for the extract chosen for these teachers notes. The extract covers aspects of her research into brain lateralisation. Use the focus questions that accompany the extract to promote discussion among your students.
Lesley Rogers was born in Brisbane in 1943. She received a BSc (Hons) from Adelaide University in 1964, where she investigated the physiology of long-necked tortoises. After this degree she spent a number of years in the USA. From 1965 to 1966 she was a teaching fellow at Harvard University and from 1967 to 1968 she was a research assistant in the Gastroenterology Department of the New England Medical Center Hospital in Boston.
In 1971 Rogers received a DPhil from Sussex University in the UK for her work on how chick behaviour was affected by testosterone and lesions of the isthmo-optic nucleus. She returned to Australia in 1972 when she was appointed as a senior tutor in the Physiology Department at Monash University. From 1976 to 1977 she was a senior research fellow at the Australian National University. From 1978 to 1985 she was in the Pharmacology Department at Monash University, appointed initially as a senior tutor, then ARC research fellow and finally as a lecturer. Her research discovered lateralisation in the chick brain, a phenomenon thought at the time to be a unique feature of the human brain.
Rogers joined the Physiology Department of the University of New England in 1985 as a lecturer. She received a DSc from Sussex University in 1987 for her thesis entitled Neuroethological Studies of Brain Development and Behaviour. In 1987 she was appointed senior lecturer and in 1989 was appointed associate professor. She was appointed to a personal chair in 1993 and is now Professor of Neuroscience and Animal Behaviour. In 1997 she received the Vice-Chancellor’s Award for Excellence in Research. Her particular research interests include the structural and functional lateralisation in the brain and the effects of early experience and hormones on brain development.
In 1997 Rogers was elected a Fellow of the Australian Institute of Biology and in 2000 she was elected as a Fellow of the Australian Academy of Science.
Is lateralisation of behaviour significant for survival?
What advantages might accompany lateralisation – or, conversely, what might be the disadvantages of its absence? Why is the vertebrate brain lateralised?
I hope to be able to tell some of the answer to that in a couple of years' time, because it is now my main theoretical interest. And again the chick model turns out to be terrific, because I can make more- or less-lateralised chicks by incubating them in the dark or the light, and then compare the cognitive abilities of those two groups.
Are unlateralised chicks in any way disadvantaged, either in the lab or in other settings?
In the lab we've done one experiment, giving the chick two things to do, which hints at that. The idea was to challenge it by asking its two hemispheres to do two different things at the same time. In the chick, the left hemisphere – and, incidentally, the right eye, because they have completely crossing optic nerves – is used preferentially for finding these pebbles versus grain in pecking to feed. And Chris Evans and Peter Marler showed that if you play to a chicken the alarm call for its own aerial predator, it looks up and scans overhead using its left eye (and hence its right hemisphere). So I designed a test where the chick is pecking on the floor using its right eye-left hemisphere, and then a little model predator comes over the top. It should then look up, using its right hemisphere-left eye for that. Once the dark-incubated, less lateralised chicks started pecking, they were slower to respond to the predator coming overhead. In a natural situation, that slower response could well be a disadvantage.
Is this where you expect your experimental, empirical interests to be directed most?
Well, one thing is to try to follow up more, in a laboratory setting, the advantage of having a lateralised brain – going ahead with these tasks that require competing input from the hemispheres and moving to other sensory modalities. But the other challenge is to ask whether what we are looking at in the lab is just an esoteric thing. Or does it for animals, as we know it does for humans, actually relate to their behaviour in the natural environment? Can you even see it in the natural environment? And now we have some evidence that, yes, animals do show lateralised behaviours in the natural environment.
Some really nice work with fish has been done in Italy by Angelo Bisazza and Giorgio Vallortigara, outside the collaborative work I do with them. Looking at various species of fish, they found laterality in some and not in others. Then they applied to the fish an idea I had, that laterality might have something to do with coordinating social behaviour.
They put one or two fish in a little internal tank and looked at how close the others came to it, so they could get an objective measure of their degree of schooling. Then they looked to see which species are lateralised or not: when a fish swims up to a barrier behind which it sees various stimuli, does it go left or right? It turned out that the ones that school are also lateralised – if they've got a population bias to go one way, then they tend to be a schooling species. (Certainly, to have that bias would keep the shoal together.) Of the ones that didn't school so much, some were lateralised but the majority weren't. So the consistent population bias of lateralisation was present in those species that have a sort of social order in their movement. But of course each different kind of lateralisation might be associated with a different selective pressure, or a different advantage. We should not talk as if it were unitary; it is probably much more complex than that.
What determines how lateralisation works?
Does some underlying common denominator distinguish the left side of the brain from the right side of the brain in most species – communication versus emotion or, perhaps, spatial processing? And if a final common denominator exists, does one side pre-empt processing at the expense of the other? If so, the big question would be which side, which function, which feature, which aspect of behaviour is the primary one. What are your thoughts on that?
Richard Andrew and I developed a model which we think applies to all vertebrate species, and certainly applies to those studied so far. The left hemisphere seems to be used to control responses that have to be considered, whereas the right hemisphere is more for immediate responses that are given without the pros and cons being weighed up.
In order for the left to fill its role, it has to suppress the spontaneous responses of the right, which is, as you mentioned, for expression of intense emotions and for spatial processing of the kind that uses a map. There are other, added aspects of function in the hemispheres, but as a general model one might say that feeding responses which require the animal to manipulate things or to inhibit pecking at a pebble in order to peck at a grain are left hemisphere: you've got to think about what you do before you respond. But if you're going to just lob an attack peck or strike at an animal – something unspecific which you have to do quickly – that's right hemisphere.
In some recent experiments I did when I was in Italy last, we looked at where a chick strikes. You put two chicks in together which haven't seen each other before. They tend to do attack pecks – not very damaging; some people call them social pecks – at each other. If you look at where they lodge those, you see that they are primarily in the left lateral field, which means right hemisphere. So, left side for attack, right side for feeding responses that have to be considered. And we have shown that the same is true in the toad. When toads strike at prey, they do so in the right hemifield, and if they make a conspecific attack strike, it's on the left. In other work, gelada baboons, if they attack the conspecific, tend to do the one on the left. Deckel, in the United States, has now shown this to be true in lizards also. There is a surprising similarity across many different vertebrates, so it seems to be a fairly basic property.
If the left and the right sides of the brain are different, how do you stand with respect to the currently popular 'educate the right side of your brain' literature? Is it drawing a long bow?
Perhaps there is something in it, but I think it is mostly a waste of time. There is no way you can force that. There may be useful psychological experiments where you really do put information in, presenting it tachistoscopically – with rapid flashes – so that people are looking straight ahead and the information is actually in the peripheral field and they're not turning the eyes to look at it. But that is not how these techniques go on; instead they get people to do all sorts of motor things.
An edited transcript of the full interview can be found at http://www.science.org.au/scientists/interviews/lr.
Focus questions
Select activities that are most appropriate for your lesson plan or add your own. You can also encourage students to identify key issues in the preceding extract and devise their own questions or topics for discussion.
behaviour
brain hemisphere
chick model
lateralisation
left-brain
right-brain
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