Lucy Taylor of Aberystwyth University has studied the relationship between the Welsh and the people of Argentina 150 years ago.
Speaking at the Eisteddfod, she said the Welsh could not claim economic, military or political dominance.
Instead they focused on moral supremacy, she said.
Dr Taylor said it could be argued this has remained relevant, through post-devolution policies such as banning smoking in public places, the introduction of a plastic bag levy and presumed consent over organ donation - all containing a moral agenda.
"The Welsh in Patagonia emphasised the principles of righteousness when they first met the indigenous people of Patagonia, and purposefully followed a path of friendship, not violence, based on a desire to exercise compassion and mercy," she added.
"They contrasted the peaceful 'Welsh way of colonisation' with the scornful and sometimes violent policies adopted by the Argentines in Patagonia and within the British Empire."
Welsh settlers asserted dominance in Patagonia by portraying Wales as a small country filled with moral giants, an academic has said.