Adelbert Ames Jr. (August 19, 1880 – July 3, 1955) was an American scientist who made contributions to physics, physiology, ophthalmology, psychology, and philosophy. He pioneered the study of physiological optics at Dartmouth College, serving as a research professor, then as director of research at the Dartmouth Eye Institute. He conducted important research into aspects of binocular vision, including cyclophoria and aniseikonia. Ames is perhaps best known for constructing illusions of visual perception, most notably the Ames room and the Ames window. He was a leading light in the Transactionalist School of psychology and also made contributions to social psychology. Formative years Adelbert Ames Jr. was born on August 19, 1880, in Lowell, Massachusetts. His father, Adelbert Ames, was a general in the Union Army during the Civil War and Reconstruction Governor and Senator from Mississippi; his mother, Blanche Butler Ames, was the daughter of U.S. general Benjamin F. Butler, a controversial military leader, politician, and unsuccessful candidate for the U.S. presidency. Apart from his military and administrative service, General Ames obtained several U.S. patents for pencil sharpeners and other mechanical devices. Ames' sister Blanche Ames Ames was a woman's rights suffragist, and his brother Butler Ames was a politician and Army officer during the Spanish–American War. His son, Adelbert Ames III (1921–2018), was the Charles Anthony Pappas Professor of Neuroscience, Emeritus, at Harvard University. In research papers, Adelbert Ames Jr. is commonly cited as Adelbert Ames II, to prevent his being confused with his father or his son. Ames attended Philips Academy, Andover, Massachusetts, then went to Harvard College, where he earned a law degree, and where his most influential teachers were George Santayana and William James (whose daughter he was also engaged to, but did not marry). After practicing law for a few years, Ames abandoned it to become a painter. For several years, while collaborating with his sister, Blanche Ames (who was also a painter), the two of them tried to determine if the quality of visual art could be improved by the scientific study of vision. Ames set about improving his knowledge of the optical components of the eye, assuming that once he had mastered them, he would return to painting. As it was, his studies mastered him and Ames made vision his life's work. Ames went to Clark University in 1914 to study physiological optics, making enough of an impression to be made one of