Colin MacLeod, a graduate of McGill University (B.A.) and the University of Washington (Ph.D.), is recognized internationally for his groundbreaking empirical work and theoretical innovation in cognitive psychology, most notably in the domains of attention and memory. For 35 years, his research has added extensively to our understanding of the fundamental cognitive processes involved in attending to, remembering, and interpreting the world around us.
From the outset, MacLeod has been fascinated by memory. He is a leading expert on directed forgetting, an experimental paradigm that models updating memory when information changes. Since his graduate days, he has championed a selective rehearsal account—that new information benefits from continuing rehearsal whereas old information stops being rehearsed. He has also argued against the other predominant view—that old information is inhibited so that new information may be highlighted. In 1998, with Jonathan Golding, he edited the first book on intentional forgetting, which began with his remarkably thorough and scholarly review.
In his post-doctoral years, MacLeod did pioneering work on individual differences, showing how strategic processing differences that derived from our broader intellectual abilities result in dramatically different ways to accomplish the same cognitive task. These studies remain landmarks on cognitive differences, cited in many cognitive texts. His expertise on individual differences in memory and cognition led him to co-write the most recent definitive review of this field as well.
Upon joining the faculty of the University of Toronto in 1978, MacLeod became a member of the best known group of memory researchers in the world, a stimulating environment that gained immensely by his presence. In the early 1980s, this group introduced the crucial distinction between explicit, conscious memory and implicit, unconscious memory. MacLeod’s work on this topic has continued for a quarter century, helping to test the transfer appropriate processing perspective—that memory is best when processing during encoding and retrieval are most similar.
Having long realized the intimate link between attention and memory, in the 1980s MacLeod began a research program on attention. A particular emphasis has been the concept of automaticity: that extended practice leads to qualitatively different processing. With then graduate student Kevin Dunbar, MacLeod first demonstrated that classic Stroop interference was not caused simply by the faster process interfering with the slower one, and then traced the development of interference with extended practice. Indeed, this constant emphasis on the powerful influence of learning is the hallmark of all of his work. MacLeod then wrote the definitive review of the Stroop literature—among the most cited papers in all of psychology over the past 20 years.
Like any top-flight scientist, MacLeod seeks to understand the basic, foundational principles of his science. But from the beginning, he has recognized that basic research often has important practical implications. Early on, he studied the profound effects on memory of anticonvulsant drugs taken by epileptic patients to control seizures, showing that memory declined as a direct function of dosage. This work, published in Science, sounded an important caution to the medical community about the cognitive costs of over-medication. More recently, he has collaborated with colleagues at the Centre for Addiction and Mental Health on a series of studies on alcohol effects on attention and memory. Linking these avenues of research is an abiding interest in the cognitive underpinnings of clinical disorders. In all these domains, MacLeod brings to bear incisive experimental skills and theoretical rigour.
Most recently, MacLeod has drawn on his unique expertise in both attention and memory to challenge one of the core theoretical constructs in cognition. In a wide-ranging review chapter, and in a book edited with David Gorfein, he argues that the concept of inhibition has been too readily extended from brain to mind. He questions the need for the concept of cognitive inhibition: Instead, he proposes that performance decrements result from conflict caused by unavoidable automatic memory retrieval, even when the retrieved experience is irrelevant.
As impressive as MacLeod’s contributions to knowledge are, they are paralleled by an extraordinary dedication to serving the academic and scientific community. Both at the University of Toronto (1978-2003) and at the University of Waterloo (2003-present), he has supervised a host of students—undergraduate, graduate, and postdoctoral: Training of young scientists clearly is a high priority for him. At the University of Toronto at Scarborough, he was Chair of the Division of Life Sciences (Psychology and Biology) and then Vice-Principal of the college. In 2002, on the occasion of the 175th anniversary of the University of Toronto, he was selected as one of the university’s “Great Minds,” a distinction reserved for only a very few faculty and alumni.
Outside the university, MacLeod’s contributions have been equally remarkable. He served on and chaired the NSERC Grant Selection Committee for Psychology, as well as serving on Psychology's NSERC Reallocations Committee twice. He has recently served on the CFI adjudication panel for Psychology as well. He has organized scholarly conferences in Canada (Lake Ontario Visionary Establishment), the United States (The Place of Inhibitory Processes in Cognition, Arlington Texas), and internationally (Tsukuba International Conference, Tsukuba Japan), and has always sought to increase the internationalization of Psychology.
In addition to service on a number of editorial boards of top-tier journals, he has performed major service for the field as Editor of not one but two major journals. From 1992-1996, he was Editor of the Canadian Journal of Experimental Psychology. From 2002-2006, he was the first non-American Editor of Memory & Cognition, one of the top two journals in the field internationally. Not surprisingly, his accomplishments have been recognized both nationally and internationally. He has been sought after as a visiting scholar worldwide, including France, Israel, Japan, and the Netherlands. He has been made Fellow of the Canadian Psychological Association, the American Psychological Association, and the Association for Psychological Science.
In summary, Colin MacLeod is an outstanding scientist who is world-renowned for his highly cited contributions to cognitive psychology and cognitive science. He is, in every respect, an outstanding recipient of the BBCS Hebb Award.