Clifford Ivar Nass (April 3, 1958 – November 2, 2013) was a professor of communication at Stanford University, co-creator of The Media Equation theory, and a renowned authority on human-computer interaction (HCI).

Nass was the director of the Communication between Humans and Interactive Media (CHIMe) Lab, co-director of Kozmetsky Global Collaboratory (KGC) and its Real-time Venture Design Laboratory (ReVeL),[4] and a co-founder of TeachAids.

[7][8] He then conducted research in the areas of computer graphics, data structures and database design for IBM and Intel before returning to Princeton to pursue graduate studies.

He received a Ph.D. in sociology from Princeton in 1986 after completing a doctoral dissertation titled "Society as computer: the structure and skill of information work in the United States, 1900-1980.

[12] Nass consulted on the design of over 250 media products and services for companies including Microsoft, Toyota, Philips, BMW, Hewlett-Packard, AOL, Sony, and Dell.

[16][17] This line of research led to the publishing of his book Wired for Speech : How Voice Activates and Advances the Human-Computer Relationship, in which he summarized the results of much of this work.

In addition to furthering the study of media multitasking, Nass also began to research the voice user interface in relation to autonomous vehicles.