Research Biography of Richard M. Shiffrin
Shiffrin has made many contributions to the modeling of human cognition in areas ranging from perception to attention to learning, but is best known for his long-standing efforts to develop explicit models of human memory. His most recent models use Bayesian, adaptive approaches, building on previous work but extending it in a critical new manner, and carrying his theory beyond explicit memory to implicit learning and memory processes. The theory has been evolving for about 35 years, and as a result represents a progression similar to the best theories seen in any branch of science.
Shiffrin’s major effort began in 1968, in a chapter with Atkinson  that laid out a model of the components of short- and long-term memory and described the processes that control the operations of memory. The Atkinson-Shiffrin model encapsulated empirical and theoretical results from a very large number of publications that modeled quantitatively the relation of short- to long-term memory. It achieved its greatest success by showing the critical importance—and the possibility—of modeling the control processes of cognition. This chapter remains one of the most cited works in the entire field of psychology.
Shiffrin’s formal theory was taken forward in a quantum leap in 1980  and 1981  with the SAM (Search of Associative Memory) model. This was a joint effort with Jeroen Raaijmakers, then a graduate student. The SAM model quantified the nature of retrieval from long-term memory, and characterized reCALL as a memory search with cycles of sampling and recovery. The SAM theory precisely incorporates the notions of interactive cue combination that are now seen to lie at the heart of memory retrieval. Another major quantum step occurred in 1984  when the theory was extended to recognition memory. With another former student, Gary Gillund, Shiffrin initiated what has become the standard approach to recognition memory, in which a decision is based on summed activation of related memory traces. It was a major accomplishment that the same retrieval activations that had been used in the recall model could be carried forward and used to predict a wide range of recognition phenomena. The next major step occurred in 1990, when Shiffrin published two articles on the list-length effect with his student Steve Clark and his colleague, Roger Ratcliff [5, 6]. This research was of critical importance in that it established clearly that experience leads to the differentiation, rather than the mere stregthening, of the representations of items in memory.
In 1997, the theory evolved in a radical direction in an important paper with another former student, Mark Steyvers . Although the changes were fundamental, the new model retained the best concepts of its predecessors, so that the previous successful predictions were also a part of the new theory. REM added featural representations, to capture similarity relations among items in memory. Building on earlier ideas by John Anderson, and related ideas developed in parallel by McClelland and Chappell, Shiffrin used Bayesian principles of adaptive and optimal decision making under constraints to guide the selection of the quantitative form of the activation functions. In addition, storage principles were set forth that provided mechanisms by which episodic experience could coalesce over development and experience into permanent non-contextualized knowledge. This latter development allowed the modeling of implicit memory phenomena, in work that is just now starting to appear in many journals, including a theory of long-term priming [with Schooler and Raaijmakers, 8] and a theory of short-term priming [with his student David Huber and others, 9]. The short-term priming research showed that the direction of priming can be reversed by extra study given to particular primes, leading to another conceptual breakthrough. A new version of the REM model explains this and other findings by assuming that some prime features are confused with test item features, and that the system attempts to deal with this situation optimally by appropriate discounting of evidence from certain features.
Shiffrin received his Ph.D. from the Mathematical Psychology Program in the Department of Psychology at Stanford University in 1968, the year after Rumelhart received his degree from the same program. Since 1968 he has been on the faculty of the Department of Psychology at Indiana University, where he is now the Luther Dana Waterman Professor of Psychology and Director of the Cognitive Science Program. Shiffrin has accumulated many honors, including membership in the National Academy of Sciences, the American Academy of Arts and Sciences, the Howard Crosby Warren Award of the Society of Experimental Psychologists, and a MERIT Award from the National Institute of Mental Health. Shiffrin has served the field as editor of the Journal of Experimental Psychology: Learning Memory and Cognition, and as a member of the governing boards of several scientific societies.
Cited Publications by Richard M. Shiffrin
 Atkinson, R. C., & Shiffrin, R. M. (1968). Human memory: A proposed system and its control processes. In K. W. Spence and J. T. Spence (Eds.), The Psychology of Learning and Motivation: Advances in Research and Theory (Vol. 2, pp. 89-195). New York: Aaademic Press.
 Raaijmakers, J. G. W., & Shiffrin, R. M. (1980). SAM: A theory of probabilistic search of associative memory. In Bower, G. H. (Ed.), The Psychology of Learning and Motivation, Vol. 14, 207-262. New York: Academic Press.
 Raaijmakers, J. G. W., & Shiffrin, R. M. (1981). Search of associative memory. Psychological Review, 88, 93-134.
 Gillund, G., & Shiffrin, R. M. (1984). A retrieval model for both recognition and recall. Psychological Reviw, 91, 1-67.
 Ratcliff, R., Clark, S., & Shiffrin, R. M. (1990). The list-strength effect: I. Data and discussion. Journal of Experimental Psychology: Learning, Memory, and Cognition, 16, 163-178.
 Shiffrin, R. M., Ratcliff, R., & Clark, S. (1990). The list-strength effect: II. Theoretical mechanisms. Journal of Experimental Psychology: Learning, Memory, and Cognition, 16, 179-195.
 Shiffrin, R. M., & Steyvers, M. (1997). A model for recognition memory: REM: Retrieving effectively from memory. Psychonomic Bulletin and Review, 4 (2), 145-166.
 Schooler, L., Shiffrin, R. M., & Raaijmakers, J. G. W. (2001). A model for implicit effects in perceptual identification. Psychological Review, 108, 257-272.
 Huber, D. E., Shiffrin, R. M., Lyle, K. B., & Ruys, K. I. (2001). Perception and preference in short-term word priming. Psychological Review, 108, 149-182.