In Appreciation: Leo Joseph Postman

Organized by Ruth H. Maki
Texas Tech University

Leo Postman

Leo Joseph Postman, professor emeritus of psychology at the University of California, Berkeley, died on April 22, 2004, of heart failure at his home in Marblehead, Massachusetts. He was 85.

Postman was a dominant figure in the study of human memory. He earned his PhD in 1946 and by 1953 had authored 47 papers and two books, notable for the exquisite clarity with which ideas were presented and for the their depth of scholarly understanding. The Psychology of Rumor, co-authored with Gordon Allport in 1947, constituted the first scientific explanation of the origin and dissemination of rumors. Experimental Psychology: An Introduction, co-authored with James Egan in 1949, was one of the fundamental texts reflecting the change in the discipline of psychology during the period following World War II, from the European theoretic basis to a new approach based on experimentation. He also published papers on rumor with Gordon W. Allport; incidental learning with Virginia Senders; time error in sensory perception; hoarding in rats with George Miller; retroactive inhibition; motivational factors in perception; and the effect of set and intention on learning and memory.

Around 1953 he became increasingly concerned with matters of learning and memory. This research resulted in a long series of studies on the relationship between learning and the intent to learn, a topic referred to as “incidental learning.” In 1958, Leo began another series of studies on the factors that produce forgetting, and would fascinate him for the next three decades. These studies led him to his preeminence as one of the principle spokespersons and architects of modern interference theory, the major theoretical account of human forgetting at the time. Not only was Postman a central developer of this theory, but more than anyone else, he was sensitive to its weaknesses. As early as 1963, he argued that the processes postulated by the theory were in a sense too effective; that is, they predicted greater forgetting than was actually observed in the laboratory.

Postman received many significant honors during his career, including the highest honor bestowed by the University of California – the Berkeley Citation – at the time of his retirement in 1987. As a teacher at Berkeley, Postman supervised over 30 doctoral students and regularly gave heavily attended seminars. But the achievement that set his contribution apart was his founding of the Institute of Human Learning, which he directed for 16 years. The Institute became the preeminent center of research in verbal learning and memory, attracting numerous postdoctoral visitors from around the world, including nearly all the major leaders in this field at the time. The Institute’s weekly colloquia, chaired by Postman, were major intellectual events that regularly drew scholars from the Bay Area. He is also a member of the National Academy of Sciences.

What follows are some selections of anecdotes and memories from his colleagues.

University of California, Berkeley

Leo Postman and I arrived on the Berkeley Campus at the same time in the fall of 1950. He was, by that time, an eminent scholar and research scientist in perception and memory. The world of psychology knew him primarily for his work with Gordon Allport on rumor, and with Jerome Bruner on motivation and perception. I first became aware of him because of his definitive review of research on the history of the Law of Effect, a paper he wrote while a graduate student. I first encountered this paper as a student working with Arthur Melton at Ohio State University, and fully expected to meet an older and more “important” person than the one I encountered in the faculty room in the Berkeley psychology department. There he was – quiet, shy, broken glasses taped together, and puffing on a pipe – friendly, but with little to say. We tried a little small talk unsuccessfully.

But because we taught together (the junior honors course for psychology majors), we talked together. All faculty and students met for about nine hours a week: a circumstance that led to rapid acquaintance and a developing friendship. Thus, I was exposed to Leo as a teacher, and saw what many others had already seen: the breadth of his knowledge, the beauty and clarity of his presentations, and the pleasure he took in discussing the nuts and bolts of research. Equally important in our developing friendship was that our wives hit it off, and the four of us would frequently have a mid-evening break for coffee and conversation.

Leo was well known for his extraordinary productivity. At least as remarkable, however, was the unusual breadth of his interests. As such, one might wonder when Leo had time to do anything but do research and write, but like many high achievers, he and his wife Dorothy found time for an active social life exploring the night life of San Francisco during the era of the beatniks and the low cost Basque and Italian restaurants centered around Columbus Avenue and Broadway.

But the focus of Leo’s life was always on research and teaching. His bibliography reveals what all of his students and colleagues would assent to: Leo Postman was a master experimentalist. The great majority of his papers are empirical and multi-experiment. He loved the strategy of the experiment and its use in closing in on answers. Leo was also a great scholar. He read incessantly and seemed to remember everything in his wonderfully organized way. And he thoroughly enjoyed talking research with students and colleagues.

Given all this, it is not surprising that his lectures were distinguished gems. To be sure, in class, he was always formal and impersonal (no jokes!). But serious undergraduates loved his lectures because of their clarity and organization, and his unmistakable interest in the subject matter. Gerald Mendelsohn, who with Stephen Glickman ran a later version of the junior major course, told of Leo’s performance as one of a number of guest speakers in the course, in which the audience burst into enthusiastic applause at the end of Postman’s lecture. It was the only lecture in the course to receive this treatment.

Leo was an old-fashioned scholar who devoted his life to his calling. But he pursued that calling with grace and always with consideration for others. I was fortunate to be his friend.

University of California, Berkeley

My first contact with Leo Postman was as a student in a year-long upper-division course in experimental psychology that he jointly taught at Berkeley with Al Riley. Later I enrolled in his undergraduate lecture class in learning and memory. Leo’s lectures were the epitome of clarity and organization, which extended to his thoughtful answers to questions from the students. Inspired and intrigued with this research field, I worked as an assistant for Leo and Riley, who were in the final stages of an extensive study of interference effects in serial learning. During my last summer at Berkeley, I helped with the statistical analyses, assisting Leo in his magical manipulation of data.

Leo and I frequently co-taught graduate seminars. The amount of effort he put into these seminars was impressive. In addition to the expected detailed bibliography supplied the students, he critically read all of this material and was prepared with typed notes to take over a presentation if a student faltered or overlooked critical points. We also collaborated on a number of research projects, producing over 10 publications, including two edited books. Whereas Leo always treated me as an equal in these endeavors, I continued to learn from him during this period of collaboration.

I will remember Leo as a dedicated academician and research scientist who devoted his energies to his students and to his science; I will remember Dorothy Postman as his supportive “backup,” who added greatly to the social interactions within the Institute and the department.

Texas Tech University

As a graduate student at Berkeley, I took a number of graduate seminars from Leo Postman and never failed to marvel at his knowledge of the literature. Each week a student would present current research on a topic. Presenters were expected to have a thorough understanding of the literature. But, it didn’t matter how thorough and compulsive the student presenter had been, Postman always knew more about the details of the studies than the presenter. If Postman did ever forget a detail, he had a stack of notecards that always included each article presented by the student and many more. It became a challenge to us to try to present an article for which Postman had no notecard. Few students ever succeeded. He had an impressive memory and an impressive ability to synthesize massive amounts of information. The lore that scientists study what ails them was not true of Leo Postman. He studied what he excelled in – namely, human memory.

Although much of Postman’s work became out of fashion with the cognitive revolution, he investigated topics that are still of current interest. From 1954 to 1961, he published nine papers that explored the conditions under which intentional learning was superior to incidental learning and the conditions under which the two were equal. In many ways these papers anticipated later findings in the levels of processing literature.

A second example of Postman’s relevance to current topics involves the application of the interference theory to the misinformation effect. Toward the end of his career, Postman and his students investigated the role of response-set interference as a mechanism for explaining the forgetting in interference paradigms (Postman, Stark, & Fraser, 1968). The idea is that new information does not cause actual forgetting of original information, but that it results in suppression of the original information. This information can become available under appropriate testing conditions.

Postman’s experiments were always very carefully designed and extensively analyzed. They were driven by theories of verbal learning and memory. They are models of good scientific inquiry. The questions that he addressed may seem irrelevant in light of today’s sophisticated models, but many of his questions about memory remain unanswered. Researchers could benefit by reading and using some of his work in modern studies of memory.


Postman, L., Stark, K., & Fraser, J. (1968). Temporal changes in interference. Journal of Verbal Learning and Verbal Behavior, 7, 672-694.

Michigan State University

University of Toronto

Yale University

Leo Postman was not the kind of mentor who focused on the pragmatics of academic advancement – no coaching about what would be needed to get tenure, why grants are important (and how to get one), or how to negotiate departmental politics (he would have been horrified at the idea of gossiping with us about his colleagues). He was quite formal with his graduate students, calling us by our last names. With his women students, he was courtly and yet conveyed respect for their intellect. Indeed, he was ahead of the times in his willingness to accept and work with women PhD students. Although formal, he was nonetheless caring towards his students: He threatened to fire one of us if he saw her again on a motor scooter without a helmet, and promised another that, if necessary, he would bail her out for political activities, but only once!

Most important, Leo Postman was inspiring: He was a superbly clear, logical thinker and an articulate speaker. His deep scholarship was informed by a broad knowledge of experimental psychology, as well as of philosophy and history of science. He read widely, keeping up with politics and literature, and he loved a good mystery. Our Monday night seminars examined methods and findings in what sometimes felt like excruciating detail, but he often pointed to aspects of the data that the writers themselves had missed. He did not enjoy listening to sloppy thinking. Leo Postman was a great skeptic and did not take shortcuts. When one of us told him (based on a secondary source) about an interesting finding reported in an untranslated book by Inhelder and Piaget, he worked with us to translate it, to satisfy himself that the finding was as reported. He listened respectfully to students’ research ideas, would always ask a critical question that got to the heart of the problem, and his eyes got big when he liked an idea or, especially, a pattern of means.

Rensselaer Polytechnic Institute

I arrived at Berkeley in the summer of 1972 to be Leo Postman’s newest grad student. Postman was quiet and kind, but his students did not spend much time thinking about either of these qualities. He was the first world-class intellect I encountered. He worked harder and thought clearer than anyone I had met up to that point in life. The more I studied with him, the more in awe I became.

Postman was most alive when discussing research. With a sense of excitement, we dove into details of theory or methodology. We tore apart proposal after proposal in an attempt to get all of the details right. If, after running a study, we found that nature did not conform to our expectations, we dove back into the details of the study or the data to garner what we could. Postman was a master at teasing and torturing the data until it revealed its secrets. Seldom was he content with simple measures such as number correct or percent recalled. There was always more that the data could reveal, and he taught us to keep looking until we found it.

Most precious were my private meetings with Postman, where we explored in more detail the results of current experiments, talked about planned experiments or theory, or talked about my dissertation work. In addition to regular weekly meetings, he always found time for a grad student’s urgent mid-week talks. Indeed, he once welcomed my apologetic non-scheduled intrusion by telling me a rare personal story. As a grad student he had worked with Edwin G. Boring at Harvard. To see the great man, Postman made an appointment with Boring’s secretary, who assigned a day and a 30-minute time slot. At the beginning of the appointed time, Boring conspicuously set a large timer on his desk, saying, “Ah yes, Mr. Postman, I believe you asked for 30 minutes.”

Although as far as I know he never expressed a preference for how he wanted to be called, no student ever called him anything other than “Professor Postman.” Indeed, this formality extended to our informal discussions among students. I remember a social occasion where a then young and brash student of Al Riley’s repeatedly referred to Professor Postman as “Leo.” The disquiet among Postman’s students was palpable. Finally one of them said something like, “You wouldn’t call him that if he were here would you?” The student replied “no.” The Postman student said, “then don’t do it now.” And that was that.

Leo Postman taught me how to think and his thumbprints remain on my intellectual soul. He also taught me how to work – mostly by example rather than by explicit direction. He was a great man and I am proud to say that he was my mentor.

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