Dr Markwell is an Australian-born former Rhodes Scholar and former deputy vice-chancellor of the University of Western Australia.
It was easy to become "very narrow under the pressure to specialise", he told more than 320 graduates during an Otago capping ceremony address at the Dunedin Town Hall on Saturday.
Specialist expertise needed to be balanced with "wider knowledge and skills".
Adopting this a broader approach enabled people to see their own specialty in context, to better understand themselves and to engage more fully in "our world of cultural diversity, of global forces, and of rapid change."
Some people seemed to have stopped thinking at a certain point, and were living on a limited stock of "frozen opinions".
"Please don't let this happen it you," he urged.
"In these times of change, more than ever before, to allow your mind to gradually close against new knowledge and insight is a form of intellectual death, which will eventually directly affect your careers."
In his role as warden of Rhodes House, Oxford, he was conscious of the "long and enduring links between Otago and the Rhodes Scholarships".
The first New Zealand Rhodes Scholar, in 1904, was Otago graduate James Allan Thomson and the country's first New Zealand-born Governor-General, Lord Porritt, was also a Rhodes Scholar from Otago.
The calibre of Rhodes Scholars coming to Oxford from Otago remained "very high".
Finishing off, Dr Markwell referred to the university's motto "sapere aude", which was generally translated as "dare to be wise".
"Today, I dare you to seek to make a difference in the world, and to do so, I dare you to be wise."
