[visionlist] Tom Cornsweet (1929-2017)

[Jack Yellott]

Vision scientists will be sorry to learn that Tom Cornsweet died on 
November 11 2017, at age 88, in Prescott Arizona, his home for many years. 
His death followed a long illness and was not unexpected. After earning a 
Ph.D. from Brown in 1955, Tom taught at Yale and the University of 
California, Berkeley, and finally the University of California, Irvine, 
where he held appointments in the departments of Cognitive Sciences, 
Electrical Engineering and Computer Science, and Ophthalmology. He retired 
from UCI in 1999, but remained active in applied research and development 
on ophthalmic instruments, as he had been throughout his career—his early 
work on eye tracking and image stabilization at the Stanford Research 
Institute (now SRI International) in the 1960s and 70s led eventually in 
1973 to the first commercially viable automated refracting device, the 
Acuity Systems 6600 Auto-Refractor. Altogether he obtained 40 patents. His 
final official position, from 2013-2015, was Chief Scientist at Brien 
Holden Vision Diagnostics, where he continued to develop ophthalmic 
instruments of his own invention.

In basic vision science Tom is probably best known today for his discovery 
of the remarkable brightness phenomenon known generally as the Cornsweet 
Illusion (or sometimes the Craik O'Brien Cornsweet Illusion, acknowledging 
earlier investigators). He described and analyzed this effect in his 
classic 1970 textbook, Visual Perception, which has always been widely 
regarded as a model of scientific exposition. This is especially true of 
its treatment of color vision—even today it remains arguably the best 
starting point for understanding color matching phenomena—and also for 
clarifying the distinction between visual phenomena, like color matching, 
where genuine scientific explanation is possible, and other phenomena, 
such as color appearance, where the private nature of subjective 
experience makes it unclear how the usual tools of science can be applied. 
Along with scientific hardware—lenses and such—Tom had a great passion for 
rigor in scientific thinking, which he shared (indeed, insisted on) with 
his students (Davida Teller being best known) and colleagues.  Those 
fortunate to work with him always found it a uniquely valuable 
experience—one is tempted to say even ennobling. He will be greatly missed 
as a scientist and as a friend.

Jack Yellott
Professor Emeritus
Cognitive Sciences Department
University of California, Irvine