Intelligence of people born and raised in Aberdeen improved with each generation, according to a new study.
Scientists at the University of Aberdeen and NHS Grampian examined two groups of people, one born in 1921 and the other in 1936.
The study consisted of 751 people all tested aged 11 and retested between 1998 and 2011. Comparison in later life found an increase in IQ of 16.5.
The researchers now hope to expand the study.
Dr Roger Staff, who led the study, described the size of the intelligence gains as "surprisingly large".
He said: "When you consider the life experiences of the two groups, those born in 1921 experienced the depression as teenagers and then World War Two.
"Those born in 1936 were children during the war and experienced food rationing.
"Although rationing meant that the food was not particularly appetising it was nutritious and probably superior to the older group.
"In addition, post war political changes such as the introduction of the welfare state and a greater emphasis on education probably ensured better health and greater opportunities."
He continued: "Finally, in their 30s and 40s, the 1936 group experienced the oil boom which brought them and the city prosperity.
"Taken together, good nutrition, education and occupational opportunities have resulted in this life-long improvement in their intelligence. Aberdeen has been good for their IQ."
He added: "These IQ gains are probably not unique to Aberdeen with similar environmental changes being experienced across the UK."
Dr Staff and the team hope to expand their work to include a group of Aberdonians who were born in the 1950s, and expect the average Aberdonian IQ to increase further.
He said: "Those born in the 50s were raised in a boom time for Britain. In addition, this group coincided with the expansion of higher education and have always lived and worked in an oil rich city."