Healthy people, including children, might one day take drugs to boost their intelligence, scientists predict.
Could brain-boosting drugs become 'as common as coffee'?
The think-tank Foresight, outlined the scenario in an independent report looking at potential developments over the next 20 years.
Such "cognitive enhancers" could become as "common as coffee", they suggest.
Scientists did not rule out children taking exams facing drug tests, as sportsmen do, to see if any have taken 'performance enhancing substances'.
The report was compiled by 50 experts, who set out their predictions for the next two decades.
Some drugs are already known to aid mental performance.
Ritalin, now prescribed to children with attention deficit hyperactivity disorder (ADHD), has already been used by some students to improve their performance in exams.
Modafinil, used now to treat sleep disorders, has been shown to help people remember numbers more effectively.
It can also make people think more carefully before making decisions.
There is also a type of molecule called ampakins, which enhance the way some chemical receptors in the brain work, suggesting drugs could be developed to improve people's memory when they are tired.
The Foresight report states: "In a world that is increasingly non-stop and competitive, the individual's use of such substances may move from the fringe to the norm, with cognition enhancers used as coffee is today".
But the availability of such drugs would open up a range of social and ethical questions, including whether it should be permitted for people to use them to gain advantage over others.
How they should be monitored would also be an issue.
Scientists said it could raise issues about what substances children undertaking exams could use.
Professor Trevor Robbins, of the Department of Experimental Psychology at the University of Cambridge, who helped compile the report, said: "No one minds very much about people taking vitamins to make them do a little bit better.
"But taking a natural, or unnatural, substance in exams might cause some ethical problems along the lines that we have in sport."
Professor Gerry Stimson, an expert in the sociology of health behaviour at Imperial College London, who also helped compile the report, said: "Would this be putting people at a fair advantage, or an unfair advantage?
"It is permitted to take drugs for therapeutic reasons, but you would need a regulatory framework for well people."
But the scientists say the drugs could become commonplace.
Professor Robbins said: "You have to look 20 years into the future.
"It's possible that these new drugs will be the new coffee, if you like, and taken by a broad range of individuals."
The report also looks at potential for vaccines against addictions to nicotine or cocaine, which would offer treatments for addicts by blocking the effects of the drug in the body.
It also looked at the potential for drugs to treat or delay the progress of Parkinson's and Alzheimer's diseases.
Sir David King, chief scientific advisor to the government, who oversaw the project, said "By examining challenging issues, such as brain science and addiction, scientists can help inform the government and others by building a strong scientific evidence base.
"This will provide the best platform to help us prepare for the future."