However, as with all attempts to ‘‘standardise’’ human attributes’ infinite variability, IQ tests merely serve as dynamic performance indicators rather than immutable, reproducible, ineluctable findings.

Personal experiences and the constant Silicon Valley/Apple/Google/Facebook drum beat seems to be convincing humans – too many – that machines ‘‘know everything’’ (‘‘Machines smart, people smarter (still)’’, January 13, p18). Algorithms feed on data happily donated by users, who don’t bother to read the small print, but consume with delight instantly gratifying responses created from their beneficence.

Machines have evolved from tools to masters. There’s no reason to believe the ‘‘mysterious trend’’ of declining IQ research revealed in Norway, Denmark, Finland and Britain, potentially attributable to mobile-phone use, would not be reproducible in Australians.

For decades the concept of brain plasticity, in expanding intellectual capacity, has been found to have validity, so there’s no reason to believe that under-use, through delegation to technology, would not have reverse effects. IQ would seem really under assault. US researchers have determined a link between obesity and smaller brain size (‘‘Large waistline linked to smaller brain’’, January 11, p9). Introduction of 5G – the-internet-of-everything – sets the scene for the perfect storm of phone pervasiveness and increasing sedentary existence!

Albert M. White, Queanbeyan, NSW

In a letter in the Sunday Canberra Times (December 13) Kevin Rattigan compared economics to astrology. This is a little unfair to astrology. Didn’t economist JK Galbraith state that ‘‘The only function of economic forecasting is to make astrology look respectable’’?

Norm Johnston, Monash

Cotton farming in the second driest continent on Earth has clearly become unsustainable, as witnessed by the catastrophic state of the Murray-Darling river system. We basically export water that would be needed to maintain a healthy river system.

Cotton production is presently economically viable only because water is too cheap and environmental costs, such as pesticide run-off, lack of environmental flows and decline of biodiversity through huge monoculture landscapes created by bush clearing are being externalised .

What needs to happen is an orderly, well-planned, well-funded transition from cotton farming to energy farming including re-skilling programs and a clear timeline of, say, 10 years.

The huge laser-levelled cotton fields are perfect sites for solar panel arrays and wind turbines (if there is harvestable wind energy in the area). This must be combined with revegetation and soil improvement to control dust and with large research projects on smart energy technologies, on energy and water efficiency and on reconstruction of and re-skilling in Aborigine land management and sustainable food production techniques.

There is an instructive precedent for such a massive transformation in the history of the German Ruhrgebiet : ‘‘The Ruhrgebiet has gone through an exemplary transformation from Germany’s blue-collar heartland into one of the country’s most vibrant regions for science and research.’’

Sadly, there is no sign whatsoever that Australian policymakers and politicians are independent, agile and innovative enough to consider such a transformation that would not only benefit local communities, but the whole nation.

Jochen Zeil, Hackett

It is well beyond time to acknowledge the reality of our nation’s history: that to the First Peoples of Australia, January 26 is a painful reminder of the invasion of their lands and the onset of the Frontier Wars and massacres, the dispossession of their forefathers and the oppression of their families.

Generations of Aboriginal children have been scattered and lost ... disconnected from all that had meaning in their lives.

The effect of this past mistreatment of Indigenous peoples is starkly reflected by holding the celebration on January 26. We must now act to acknowledge the resilience and resistance of First Peoples in the face of that invasion, and their ongoing survival as one of the oldest living cultures on the planet.

It is time to move on from the colonial attitudes of the past and to recognise that this date is a day that cannot unify our nation.

We need a new day ... a day that can be celebrated by all Australians: a day that respects the First Australians of our nation. I support the move to a date that all Australians can enjoy and that celebrates the people of our nation: Let’s call it Australians’ Day.

Christine Bennett, Woombye, Qld

ACT Labor-Green’s continuing West-Basin-real-estate-driven inclusion of Commonwealth Avenue in the Civic-Woden tram route remains a basic mistake.

The Commonwealth recently applied valid pressure to exclude the Parliamentary Zone, where foreign-body trams would unacceptably pre-determine future development.

The ACT’s latest iteration (at least until after the federal election) uses the whole length of Commonwealth Avenue, with massive engineering/urban-design/disruption problems, and costs at each end, and on the bridge itself. And, the tram would wreck the heritage, ambience, and arboreal splendour of Commonwealth Avenue, and destroy the important symmetry with Kings Avenue Bridge.

Better to go politics-free, via New Acton, Acton Peninsula south; a new Griffin-esque, sailboat friendly, tram/bike/pedestrian bridge; a shared zone across an expanded and developed-for-people Lennox Gardens; Flynn Drive; and the State Circle cutting – partially express at peak hours.

Jack Kershaw, Kambah

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