Lee Brooks


Lee left a lasting mark

I just saw this news, searching for some papers of his to pass on to some colleagues. I lost touch with Lee, but I always expected to see him again.

New contributions appear to be closed, so I am writing my tribute as a response to the most appropriate post that I can find in this set…


I studied psychology with John Vokey, in the late 1970?s, early 1980?s. I worked in a different sub-area (psychophysics) but Lee took me under his wing. He allowed me to do mentored research in his lab. He joined my doctoral committee and critiqued my ideas and, especially, my methodology.

I thought I knew a lot about the philosophy of science when I came to McMaster. I had studied philosophy as an undergrad. Lee gently, but enthusiastically, made me realize how little I knew and what fascinating ideas were on my horizon. Kuhn was a starting point. But his approach to nonanalytic concept formation was an education in itself in questioning one’s assumptions, holding the “obvious” up to scrutiny, and thinking through how to create a credible critique of things that everyone “knows”.

Lee was remarkably patient with me, before I graduated and after. He was always helpful.

As a teaching assistant for his cognition course, I discovered that he was sensitive, perhaps too ready to accept (or worry about) criticism (especially criticism of his teaching). I learned a lot about the humility of teaching from him, the art of being the authority in a class while recognizing that there is much to improve and the students can and will point that out and deserve your attention when they do. I apply that teaching every day, now, as a teacher myself.

Lee was one of the small set of teachers who left a lasting mark on my career and my persona. I will miss him forever.

– Cem Kaner

This post was submitted by Cem Kaner.

A great scientist

I only met Lee in person once (in Cambridge in around 1999, when he attended a conference I was co-organizing), but I’m a long-time follower of his work, and he provided a number of signed, very useful and wonderfully full, reviews of my articles. It’s very sad to hear of his death.

This post was submitted by Andy J. Wills.

Lee was my mentor before the word was used for this relationship

I was an assistant professor at McMaster 1970-74. I have always said that, although I did teaching and earned my salary, it was like doing what we would now call a post-doc, under Lee’s supervision. He rounded out my education in psychology. We talked constantly; he was across the hall most of the time I was there. I came to think of him as one of the smartest people I knew. Also underappreciated. Not UN-appreciated, but he certainly should have been more famous than he was. In part, he didn’t try. He just wanted to find the truth.

We also talked politics, constantly. He was always arguing the conservative side, because I was farther left than I am now. Now I think we would agree about political matters. I also learned a lot from him about Canada. In many ways I’m sorry we did not stay there. Although I was out of touch with Lee for many decades, the thought that he isn’t around any more is a sad one.

Jon Baron (This email address is being protected from spambots. You need JavaScript enabled to view it.)

This post was submitted by Jon Baron.

Dad’s Obit (Globe and Mail)

Here is a link to Dad’s Obit in the June 12th Globe and Mail

BROOKS, Dr. Lee R.
Passed away on Wednesday, June 2, 2010, after a long struggle with cancer. He was a friend, mentor and colleague to many through his years of dedication in the psychology department at McMaster University. He is survived by his wife and partner of 50 years, Carol Brooks (Flora), his two children, Eric Richard Brooks of Woodenville, WA. and Corinne Carol Brooks Claypool of Savoy, IL. Loving grandfather to Kaylin Christine Claypool. Loving brother to Seba Phingston of California. Memorial Service to be held at a later date. Remembrances and condolences would be gratefully accepted at: www.DrLeeBrooks.com

Academic History

The general topic I am interested in is concept learning and the process of gaining sensitivity to complex structure. This general topic breaks down into several specific areas. Medical diagnosis. When reading a textbook list of the rules for diagnosing a disorder and looking at the illustrations of the key features, it is hard to believe that diagnosis of the disorder could be difficult. The experience, however, is very different. Our research program has been aimed at understanding some of the sources of difficulty.

1. Difficulty in noticing the obvious. We have two lines of evidence that the perception and reporting of supposedly obvious features of patient appearance is strongly influenced by contextual factors. Both experts and students gained 20% in diagnostic accuracy by having textbook examples of features verbally described for them. Both experts and students reported from 15 to 30% more of these features when the correct diagnosis was suggested to them. The informal report by experts and students alike was that they simply had not noticed features that then seemed clear after they were pointed out. We believe that this is a major characteristic of many medical stimuli, and one that results from the large number of potential categories, the presence of many variations of normal features, and the relatively low redundancy of these stimuli. (Norman, LeBlanc & Brooks)

2. Disadvantage of Searching Medical Stimuli without a Diagnostic Hypothesis. Students who were instructed to avoid making any diagnosis until after they had worked down a list of all potential features for the disorders under consideration came to 1/3 fewer correct diagnoses than did a group that was asked to make a diagnosis first and then report the features. The "feature first" subjects informally reported that they wound up with so many potential features that they became confused with incompatible possibilities when confronting the list of diagnoses. (Brooks, Colle, Hatala & Norman)

3. Influence of similar prior instances. Different prior cases may come to mind under different circumstances. The prior cases that do come to mind might help in guiding the search for relevant features. The variability provided by depending on a wide variety of prior cases might help to explain big variations in the reliability of diagnosis. (Brooks, Allen & Norman, 1991; Norman, Brooks, Coblentz, & Babcook, 1992).

Implicit structure. Without deliberately trying to, people often become sensitive to the structure of a domain, such as musical style or even the design of an experiment in which they participate. We have documented a strong nonanalytic contribution from prior episodes in this kind of learning.

1. Abstract analogies in artificial grammars. In an artificial grammar experiment subjects are given sets of consonant strings to memorize. They then are told that these strings were generated by a complex set of rules and are asked to judge whether new strings are or are not consistent with those rules. Subjects perform well above chance on this even though they claim to not have been looking for rules while memorizing. We have shown that a major portion of this ability is due to similarity between test strings and particular training instances. even when the literal surface elements are changed. Reber (1969, 1989a) and Mathews et al (1989), in experiments on learning artificial grammars, reported good transfer to letter strings consisting of letters not used in the training stimuli, provided that the same grammar generated both training and transfer strings. They conclude from this that the transfer predominantly relies on abstract knowledge. We report an experiment showing that much of the transfer to "changed letter set" strings is due to abstract similarity between test strings and specific training stimuli. That is, a string such as MXVVVM could be seen as similar to BDCCCB without implying that regularities common to a large number of training items had been abstracted. We conclude that reliance on an abstract (relational) analogy to an individual item must be distinguished from reliance on knowledge of the structure of the grammar abstracted across many training items (Brooks & Vokey, 1991).

2. Learning the experimenter's design. One premise of the artificial grammar literature is that people are continually gaining sensitivity to the structure of the world around them. In this paper we demonstrate that this sensitivity to structure extends to general memory experiments as well as the experiments deliberately designed to investigate structural learning. Rules that experimenters use to select words for memory experiments, such as frequency, length and grammatical class, produce consistencies to which subjects can become sensitive. Replicating the key results from the tacit learning literature, subjects in our experiments discriminated new words consistent with the experimenters' selection rules from inconsistent words, even when they could not describe those rules. The results also reveal a close relation between the information underlying recognition memory and classification judgments. In particular, a "mirror effect" (Glanzer & Bowles, 1976) is found with both tasks. (Higham & Brooks, 1997)

Coordination of analytic and nonanalytic knowledge. One of the overarching themes of research on natural concepts over the last 25 years is that our knowledge of the world is generally inexplicit: We judge items to be members of categories and anticipate their properties with reference to category prototypes or by comparison to previously experience instances of the category. However, in laboratory experiments, people persistently look for and use rules. Even some of the evidence that was originally taken to support the use of instances can be better fit by models that assume people are seeking rules (Nosofsky, Palmeri & McKinley's RULEX model). This discrepancy between the observed behavior of people in the laboratory and their inferred behavior in the world is, in our view, the major issue that need resolution in this field.

1. Identification in the service of use: Most people seem to believe that natural categories have perfectly predictive defining features. They do not easily accept the family resemblance view that the features characteristic of a category are not individually consistent enough to act as a simple rule. But common categorization tasks in the laboratory do not produce this "simpler than it is" belief. If there is not a simple classification principle in these tasks, the subjects know that fact and can report it. We argue that most laboratory tasks using family resemblance categories do not result in the everyday "simpler than it is" belief because the stimuli and the tasks encourage analysis of identification procedures during training. In order to simulate the learning that occurs under many natural circumstances, we describe a procedure, diverted analysis, in which the subjects' analytic abilities are diverted from the way in which the stimuli are identified to the use to which those stimuli are to be put. This procedure has the effect of providing a special role for "family resemblance" data structures, unlike the situation with more analytic training procedures. We also suggest that the informational descriptions of the stimuli commonly used in laboratory tasks are better suited to describe the subjects' analytic behavior than their impressions of consistency that are critical to their belief in the existence of perfectly predictive features. Finally, we discuss the prevalence of "diverted analysis" in everyday categorization tasks.

2. The erosion of analytic control of classification: One hypothesis we entertained was that possibly people originally developed rules (attention to salient predictors) to guide classification, but that with practice, they would start relying more on similarity to prior, well known instances. This process of retrieval would likely be easier, faster and generally yield the same answers as the rules, since the more similar prior items would probably be in the correct category. To investigate this, our participants received a classification rule and practice classifying a set of stimuli. Test stimuli included items very similar to training items, with expectation of observing a shift from classification by rule to greater reliance on similarity. However, the only similarity effect occurred by generating false recognitions, which went down with practice. Otherwise, people applied the rule to any items they recognized as new, even though they were slowed at applying the rule than they were in categorizing the new items they mistakenly thought were old. Variables ineffective in producing the shift include: Increasing practice, training with many close variants of category members, confounding many salient features with category membership. If our original hypothesis had been correct, it would have helped to explain the general discrepancy between laboratory performance and inferred behavior in the world. (Regehr & Brooks, Wood & Brooks)



  • Brooks, L.R., Colle, C., Hatala, R. & Norman, G.R. (1997). A disadvantage for searching medical stimuli without a diagnostic hypothesis. Submitted.
  • Brooks, L.R., LeBlanc, V., & Norman, G.R. (1997). Some conditions on support theory. Submitted
  • Brooks, L.R., Norman, G.R., & Allen, S.W. (1991). The Role of Specific Similarity in a Medical Diagnostic Task. Journal of Experimental Psychology: General, 120, 278-287.
  • Brooks, L.R., & Vokey, J.R. (1991). Abstract Analogies and Abstracted Grammars: A Comment on Reber, and Mathews et al. Journal of Experimenta Psychology: General, 120, 316-323.
  • Higham, P.A., & Brooks, L.R. (1997) Learning the experimenter's design: Tacit sensitivity to the structure of memory lists. Quarterly Journal of Experimental Psychology. February issue
  • Norman, G.R., Brooks, L.R., Coblentz, C.K., & Babcook, C.J. (1992). The interdependence of feature and category identification in diagnostic radiology. Memory & Cognition, 20, 344-355
  • Norman, G.R. LeBlanc, V. & Brooks. L.R. (1997). On the difficulty of noticing obvious features in patient appearance. Submitted.
  • Regehr, G. & Brooks, L.R. (1993). Perceptual manifestations of an analytic structure: The priority of holistic individuation. Journal of Experimental Psychology: General
  • Wood, T. & Brooks, L.R. (1997) On the erosion of analytic control.





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