Twelve men and nine women, whose work is as diverse as studying the racial elements in perceptions of crime and translating contemporary Arab poetry, have been named the 2014 fellows of the John D. and Catherine T. MacArthur Foundation. The fellowships, based on achievement and potential, come with a stipend of $625,000 over five years and are among the most prestigious prizes for artists, scholars and professionals.

The awards are being announced on Wednesday by the foundation, which is based in Chicago.

The oldest fellow this year is Pamela O. Long, 71, a historian of science and technology in Washington, whose work explores connections between the arts and science. The youngest is Danielle S. Bassett, 32, a physicist at the University of Pennsylvania, who analyzes neuron interactions in the brain as people perform various tasks. She seeks to determine how different parts of the brain communicate and how that communication changes with learning or in the aftermath of a brain injury or disease.

When she received the call informing her of the no-strings-attached windfall, Ms. Bassett recalled being stunned into silence.