Psych 159: Physiological Basis of Perception

Instructor: Don MacLeod

Class meetings: Lectures, Tuesday and Thursday 12.30 am to 1.50 pm, 1507 Mandler

Office Hours: Wednesdays, 10-12, Room 5121 McGill; Tel 534-3975.


Web:  (and click on “courses” link)

Final Questions (from last year): here

Aims and scope: We consider the process of perception as a causal chain that starts with the sensory stimulus and continues through successive stages of neural representation, culminating finally in the construction of a behaviorally useful representation of the environment. We will be aiming for a research-level treatment of current understanding of selected topics. To make this job easier, we consider mainly visual perception, and select a limited number of problems within that field for in-depth treatment, especially those for which the nature of physiological constraints on perception is clearest. The inquiry focuses particularly on how both subjective (or "psychophysical") and objective (electrophysiological, neuroanatomical) approaches can be brought to bear on the same issues about visual processing, and on the difficulties and successes in achieving consistency between the findings of the two approaches.

Format: This is a seminar style class, with active participation encouraged/required by the relatively small size of the group. The text chapter or other reading for each meeting should be done in advance. In class, much of the time will be group discussion elaborating on the reading. Discussion will be framed by both lectures (mostly by me) and presentations by students. The lectures will use the topics in the reading as a starting point. But they will not necessarily follow the reading very closely—they will leave out some topics, and often introduce new material to update and elaborate the discussion in the text, The lectures, and your own presentations, will use the readings as a stem onto which a lot of more advanced material will be grafted. For that reason, but also because participation in class will contribute to your grade, you should consider the lectures mandatory rather than optional, if you want to do well.

Text:Seeing: The Computational Approach to Biological Vision’, by Frisby and Stone.  Keep your Psych 102 texts as background; especially useful is Sensation & Perception by Jeremy Wolfe and others. (Sinauer, 2006), but other “Introduction to Sensation and Perception” books, notably Sekuler and Blake’s, are nearly as helpful.

In addition to the text, I plan to include quite a few brief on-line readings, that you should download and peruse before the relevant meeting of the class. These additional assigned readings are mostly yet to be chosen (denoted by TBA below). They will mostly be just a few pages but they will generally be dense and perhaps somewhat challenging to read with insight. Favored sources will be primary journals like Nature and Science, popular summaries like Science News, brief reviews from Trends in Cognitive Science or Trends in Neuroscience.

I will want each of you to email me, by midnight the day before each class, at least one question. discussion point, or interesting Web link, relevant to the topic of the day or inspired by the assigned reading, that you think would be helpful for stimulating or guiding discussion. We will discuss a selection from these in class. To be useful, these questions should ideally reflect some thoughtful attention to the reading or perhaps some relevant exploration on the internet.

·         Please email me your question, comment or Web tidbit by midnight the day before each class; I will collate them and bring them to class and/or post them online.

·         Where possible, please include in your text some relevant quote and/or page number from the reading.

·         Please put Psychology 159 in the subject line of your message.

·         Please limit the length of your submission to a couple of sentences

·         Please be prepared to introduce your point briefly in class.

Prerequisites and desiderata: Psych 102, Introduction to Perception, is listed as required. Confident students are not excluded, however, especially if they have some background in neurobiology or physiological psychology. As perusal of the text will show, quite a few of the topics we consider will be treated quantitatively, so an enthusiasm for thinking quantitatively, or some background in physics or engineering, is also a great advantage…and an aversion to thinking quantitatively is a corresponding handicap!

Evaluation (tentative plan):

Tentative plan is to have only a final exam (no midterm).  Besides this you are asked to produce one substantial paper  and one 15 minute presentation to the class.

The paper will be due (tentatively) at the beginning of class on Thursday of Week 7. A recommended length is 10 pages (double spaced type please). The choice of topic is up to you, provided it's relevant to the themes of the course. Discuss it with me first if you're uncertain. Originality will be appreciated, but it isn't mandatory. I can suggest possible topics and possible choices will be discussed in class. You should choose a topic and tell me your choice at least a week before the paper is due. Of course, I expect you to consult the research literature beyond the recommended readings in preparing your paper.

·         Format of the paper is flexible, but: use citations in your paper to justify your claims.

·         Cite authors by name and date, e.g. (Smith & Jones, 1922).

·         Include complete references at the end of the paper (complete citations; format is not important, APA is one standard format).

·         Include an abstract (a summary of the key points, in less than 1 page).

·         You could replace the paper with a more concrete project: for instance you could conduct a perception experiment (to help in my lab is a possibility) , do a computer simulation, or create an informative visual demonstration.

·         Please submit the paper to me by email as well as a hard copy. If you do a project, it should be accompanied by a short written report.

Your presentation should be a short and snappy but comprehensible (to your classmates) account of some topic relevant to the day’s topic. It’s a good idea to discuss your choice of topic with me beforehand. One possible choice (but not the best one) is to just summarize and clarify part of the reading we are dealing with on the day of your presentation, hopefully developing your own understanding of that topic using other sources like the recommended readings. Much better is to introduce some new material that has some loose connection to the material in the text (for instance, briefly summarize some recent piece(s) of research that have something to say about the topic of the day).  No need to be too constrained…pick something that interests you.

It’s a good idea to use some graphics for your presentation. PowerPoint is a good way to go. We will have a computer graphics projector. If you can use your own laptop (with VGA output; if you don't have a VGA connector, please bring an adapter or let me know), that will be fine. Otherwise, I will generally have mine. If you plan we have

Tentative distribution of points: Paper/project/presentations (25% for each of two), final (30%) and class participation (20%).

The final exam will be mainly or entirely essay type questions, perhaps also some short answer/multiple choice questions—perhaps a 80/20 split between essay type and short answer questions in the total grade. Tentative format for essay questions: you will be asked to answer 3 (final) out of 5 questions. These 5 questions will be selected by us from a list of up to 30 questions that I will give out at the lectures, at least a week in advance of the exam. Questions and grading will try to reward understanding rather than detailed factual knowledge. Of the material in the text, the most important topics will be the ones emphasized in the lectures, and the most important material within each topic is the material that is essential to our understanding of the subject, rather than specific facts. Answers will require thoughtful consideration of readings and lectures.





Week 1 Tuesday: Organizational meeting.

Week 1 Thursday: The problem of perception

Reading: Chapter 1 of Frisby and Stone

Chapter1         Seeing: What is it?                  Page 1



Week 2 Tuesday April 7: Vision after prolonged blindness

Power Point about Mike May

Read about our work with Mike May here:


Week 2 Thursday April 9: Evolution and Vision: the big picture

Hoffman Interface Paper (local copy)

Evolution of Eyes

Hoffman Interface Theory of Perception Presentation

Nilsson and Pelger's simulation of eye evolution


Week 3….Tuesday 14, Thursday 16: Perception as an Inverse Problem; exploiting natural constraints

Chapter 2        Seeing Shape from Texture     29


Week 4 Tuesday April 21:

Chapter 3        Seeing with Receptive Fields 55

Power Point from my lecture on optics (more detail than you need)

Why isn't vision perfect?


Chapter 4        Seeing Aftereffects: The Psychologist's Microelectrode        75


Week 4 Thursday April 23: 

Chapter 5        Seeing Edges  111


Week 5 Tuesday April 28:

Chapter 6        Seeing and the Retina 133

Power Point from my lecture on photoreceptors and visual sensitivity 

Week 5 Thursday April 30: 

Chapter 7        Seeing Figure from Ground    155


Week 6 Tuesday May 5:

Chapter 8        Seeing Objects            173

 Week 6 Thursday May 7:

Chapter 9        Seeing with Brain Cells          205

Chapter 10      Seeing with Brain Maps          229 

Week 7 Tuesday May 12:

Chapter 11      Seeing and Complexity Theory         255

Chapter 12      Seeing and Psychophysics     281

Week 7 Thursday May 14: PAPER DUE: brief presentations based on your papers

Week 8 Tuesday May 19:  TBA or break (Don out of town)

Week 8 Thursday May 21:  TBA

Chapter 13      Seeing as Inference     307


Week 9 Tuesday May 26:

Chapter 14      Seeing Motion, Part I  325

Chapter 15      Seeing Motion, Part II            355


Week 9 Thursday May 28: 

Chapter 16      Seeing Black, Gray, and White          373

Chapter 17      Seeing Color   397


Week 10 Tuesday June 2: Stereo Vision, Cue Combination

Chapter 18      Seeing with Two Eyes, Part I 419

Chapter 19      Seeing with Two Eyes, Part II            465

Chapter 20   Seeing by Combining Cues     497

Week 10 Thursday June 4:  Perception as a constructive process; The Symbolic Representation and its Computation

Chapter 21      Seeing in the Blocks World    511

Chapter 22   Seeing and Consciousness      527

Chapter 23      Seeing Summarized    539


FINAL: as in schedule of classes


Additional recommended reading: general

An outstanding introduction to the physiological basis of hearing is Schnupp et al.,  Auditory Neuroscience: Making Sense of Sound MIT, 2012. Independent of that, the associated web site, is a superb collection of auditory demonstrations with explanatory notes. Good material for a class presentation.

As for vision, if you want to do well (and still more, if you are keen to advance your understanding of the subject) you will want to read further. For a start, anyone who hasn’t completed Psych 102 might find it useful to look over a more introductory (Psych 102 or equivalent) text for review of background. Two good examples:

R. Sekuler and R.Blake, Visual Perception, Knopf, 1985

E.B.Goldstein, Sensation and Perception, Wadsworth, 1989 ( a little more physiologically oriented, and so marginally preferable here, to Sekuler and Blake).

T.N.Cornsweet, Visual Perception, Academic Press, 1970 is that rarity: a thinking person’s textbook. Fun, but limited to low levels of visual processing that can be understood in physiological (or at least in mechanistic) terms.

Richard Gregory, Eye and Brain, Princeton, 1990 is shorter, more selective, less technical and even more fun than Cornsweet.

S. E. Palmer, Vision Science: From Photons to Phenomenology, MIT 1999 is an excellent and comprehensive survey of our understanding of visual perception, encompassing phenomenological and cognitive as well as physiological viewpoints.

Useful for a more advanced and up to date, mathematically oriented survey of most of the course material: Wandell B.A. Foundations of Vision. Sinauer Associates Inc., 1995.

Still more advanced, but useful for getting into current issues in preparing papers, are the proceedings of recent scientific symposia:L. Spillmann & J.S. Werner (Eds.) Visual Perception: The Neurophysiological Foundations. Academic Press 1990 and C. Blakemore (ed.). Vision: Coding and Efficiency, Cambridge (1990).  These are sophisticated summaries of current thinking at the frontiers of research.


Recommended reading: specific topics

Other books recommended for a clear and comprehensive account of part of the material:

P.K. Kaiser and R.M.Boynton, Human Color Vision, Optical Society of America, 1996. This discusses not only color vision but also visual sensitivity (altogether, about 1/3 of the course material) in a sufficiently advanced but understandable way. Most useful are chapters 1-7 and 10, especially chapters 5, 6 and 7.  For a state-of-the-art discussion of current issues in color vision you could also try R. Mausfeld and D. Heyer, Colour Perception: Mind and the Physical World, Oxford, 2003.

D. Marr, Vision, Freeman, 1982 is the most influential book on vision written this century, outlining what has become known as the "computational" approach, which unites the artificial intelligence and physiological points of view on vision. Especially good on stereo.

Chapter 4 of The Computational Brain, by Pat Churchland and Terry Sejnowski, is a good briefer treatment along Marr's lines, again concentrating on depth and 3D shape.

S. Zeki, A Vision of the Brain, Blackwell, 1993 is a beautifully illustrated but peculiarly one-sided and controversial discussion of the special role of different regions of the cerebral cortex in vision. A broader and less idiosyncratic, but less up-to-the minute, account of the physiological basis of vision with a focus on the cortex is D.H.Hubel, Eye, Brain, and Vision, Freeman, 1988.

R. W. Rodieck, The First Steps in Seeing, Sinauer, 1998. is a challenging in its rigor and attention to detail, but it is written clearly so that an interested and thoughtful reader can understand it without much prior knowledge. Focus is heavily on early stages in vision, mainly the eye and the retina. Complements Zeki, where the focus is on cortex.


D.B. Dusenbery, Sensory Ecology, Freeman 1992 is an interesting survey of sensory processes in animals.


David M. Regan, Human Perception of Objects, Sinauer, 2000 discusses in some depth the early visual processing of spatial form defined by luminance, color, texture, motion, and binocular disparity.


A few of the many useful Web resources: