Two Americans won the 2002 Nobel Memorial Prize in Economic Sciences on Wednesday for using psychological research and laboratory experiments in economic analysis.

Daniel Kahneman, 68, a U.S. and Israeli citizen based at Princeton University in New Jersey and Vernon L. Smith, 75, of George Mason University in Fairfax, Va., will share the roughly $1.6 million Cdn prize.

Kahneman has integrated insights from psychology into economics, especially concerning human judgment and decision-making under uncertainty, the Royal Swedish Academy of Sciences said in its citation.

Smith laid the foundation for the field of experimental economics, demonstrating the importance of alternative institutions.

Last year, three Americans won the prize for advances in ways to analyse markets that can be applied to both developing and advanced economies.

George A. Akerlof of the University of California at Berkeley, A. Michael Spence of Stanford University and Joseph E. Stiglitz of Columbia University were cited "for their analyses of markets with asymmetric information," referring to the fact that some market players have better information than others.

Past awards also have recognized research on topics ranging from poverty and famine to how multinational corporations reap profits, and theories on how people choose jobs and the welfare losses caused by environmental catastrophes.

Wednesday's announcement of the economics prize was the second Nobel of the day after the chemistry award went to John B. Fenn of the United States, Koichi Tanaka of Japan and Kurt Wuethrich of Switzerland for inventing techniques used to identify and analyse proteins that have revolutionized the search for new medicines.

The medicine, physics, chemistry, literature and peace prizes were established in the will of Alfred Nobel, the Swedish industrialist and inventor of dynamite, and were first awarded in 1901.

The Bank of Sweden Prize in Economic Sciences in Memory of Alfred Nobel was established separately in 1968 by the Swedish central bank but is grouped with the other awards. It was first awarded in 1969.

The physics winners were announced Tuesday, a day after the awarding of the medicine prize. The literature prize winner will be disclosed Thursday and the Nobel Peace Prize on Friday in Oslo, Norway.

The prizes are presented to the winners Dec. 10, the anniversary of Nobel's death in 1896.