Department of Psychology
Department of Psychology

Leslie B Cohen

Professor EmeritusPh.D., University of California, Los Angeles

Leslie B Cohen



Perception, memory and cognition in infants


Les Cohen was Professor of Psychology in the Developmental area and the Cognitive Systems area at UT until his retirement in 2010. He was the founding editor of the journal Infancy, published by the International Society on Infant Studies. Dr. Cohen was elected President of ISIS for the years 2006 to 2008.

Dr. Cohen received his Ph.D. from UCLA in Developmental Psychology. His primary research interests are in perception, memory, and cognition of infants. In general, he and his students in the Infant Cognition Laboratory examined how infants process and integrate visual and auditory information from their environment. Most research projects involve some variation of a visual habituation paradigm, which Dr. Cohen developed for use in infant research. In this paradigm, infants' looking times are recorded while they are repeatedly shown either a single stimulus or multiple stimuli and are then tested with familiar versus novel stimuli. Most of the stimuli are actual events generated through sophisticated computer animation techniques or videotaped and then presented to the infants. The laboratory also developed Habit 2000, a multipurpose software program for testing infant perception and cognition. Habit 2000 is currently being used by more than 30 infant laboratories around the world.

Some of the specific research questions being investigated by Dr. Cohen are:
1. How do infants come to understand concepts and categories?
2. What principles govern infants' early language?
3. How do infants process causal relations and other visual events?
4. At what age do infants perceive both the form and function of objects with which they interact?


Cohen, L.B. & Cashon, C.H. (2000, July). A puzzle in infant face perception. Poster presented at International Conference on Infant Studies, Brighton, England.

Marks, K.S. & Cohen, L.B. (2000, July). Infants' reaction to addition and subtraction events.  Poster presented at International Conference on Infant Studies, Brighton, England.

Cashon, C.H. & Cohen, L.B. (2001, April). Developmental changes in infants' processing of faces. Symposium paper presented at the Society for Research in Child Development Meeting, Minneapolis.

Cohen, L.B. (2001, April). Uses and Misuses of Habituation: A Theoretical and Methodological Analysis. Symposium paper presented at the Society for Research in Child Development Meeting, Minneapolis.

Chaput, H. H. & Cohen, L. B. (2001, August). A model of infant causal perception and its development.  Poster presented at Cognitive Science Society Meeting, Edinburgh.

Cohen, L.B. (2002, April). Can infants really add and subtract? Invited debate presented at International Conference on Infant Studies, Toronto.

Cashon, C.H. & Cohen, L.B. (2002, April). U-Shaped Development in Infants' Processing of Faces. Poster presented at International Conference on Infant Studies, Toronto.

Cohen, L.B. & Chaput, H.H. (2002, April). Modeling the Development of Infant Causal Perception. Symposium paper presented at International Conference on Infant Studies, Toronto.

Cohen, L.B. & Cashon, C.H. (2003, April). An Information Processing Approach to Infant Face Perception.Symposium paper presented at Society for Research in Child Development Meeting, Tampa.

Cashon, C.H., Cohen, L.B. & Gora, K. (2003, April).Evidence for infants' categorical perception of face orientation. Poster presented at Society for Research in Child Development Meeting, Tampa.

Cohen, L.B.(2004, May). The Development of Infants' Perception of Causal Events. Symposium paper presented at International Conference on Infant Studies, Chicago.

Cohen, L.B., Cashon, C.H. & Rundell, L. (2004, May).Infants' Developing Knowledge of a Causal Agent.Poster presented at International Conference on Infant Studies, Chicago.


PSY 418 • Statistics & Research Design-W

43815-43820 • Spring 2010
Meets TTH 930-1100 NOA 1.116

Psychology 418-Spring 2010
Statistics and Methods in Psychology

Unique #s:    43815, 43820    Instructor:     Dr. Les Cohen
Time:        T, Th  9:30 -11:00    Office:     SEA 4.238
Room:          NOA 1.116    Office Hrs:     T, Th 8:00 - 9:15, by appt.

TA#1:  Wendy Smith         TA #2:  Grant Baldwin

Lab:   W 9:00 - 11:00, SEA 2.122    Lab   W 9:00 - 11:00, SEA 2.124
Office:             Office:    
Office Hrs:        Office Hrs:   
Email:    Email:                           
Required Reading:  

(Jackson)  Jackson, S. L. (2009). Research Methods and Statistics: A Critical Thinking Approach  (3rd Edition).  Belmont, CA, Thomson/Wadsworth

Caution: The Psychology Department will drop all students who do not meet the following prerequisites: PSY 301 with a C or better; Math 302 or a higher--level mathematics course; and a major in Psychology.

Course Requirements:

1. Papers:   Two papers are required for the course.  Each paper should be approximately 10 typewritten, double-spaced pages.  Since the course fulfills a "substantial writing requirement", your papers will be evaluated for both content and clarity of style, and you will receive helpful feedback so that your writing will improve.  The style of each paper should conform to APA guidelines as described in Jackson.  More details will be provided soon.

2.    Exams:  There will be three one-hour examinations.  Each will contain a number of multiple choice and a few short answer questions, and each exam will cover 1/3 of the course.  A few questions will require some calculations, so an inexpensive calculator (with a square root key) will be necessary.

3.    Helpful Hint: Attend all classes and labs!  At least 75% of the material on the exams will be covered in these classes!  Much of that material will be an extension of the information presented in Jackson and will not be in the book per se, but you are still required to learn it.

4. Homework:  In addition to the papers and examinations there will be weekly homework problems.  Most of these problems will be given out in your lab each Tuesday to be turned in and discussed the following Tuesday.  Some will be illustrations of statistical methods or design problems that have been discussed during the week.  Others will be more directly related to the research projects you will be conducting for the class. Many homework assignments will also involve some writing.  Homework assignments must be picked up and turned in at the appropriate time or they will not receive full credit.

5.  Policies:  Students who miss an examination without making prior arrangements will be given a zero for that exam.  Late papers will be accepted but will be graded more stringently than those turned in on time.  Cheating on exams, plagiarism, or unauthorized tutoring on papers will result in an F for the course. The University of Texas at Austin provides upon request appropriate academic accommodations for qualified students with disabilities.  For more information, contact the Office of the Dean of Students at 471-6259, 471-4641 TTY.

6. Grading:  Grading will not be on a curve so it is theoretically possible for everyone to receive an A.  It is possible to earn a total of 100 points.  The points for each requirement and grade distributions are shown below:

1st Paper     20     A      = 92  - 100   (90-91 =A-)
2nd Paper     25    B     = 82  - 87    (80-81 = B-; 88-89=B+)
1st Exam     15        C    = 72  - 77    (70-71 = C-; 78-79=C+)
2nd Exam     15        D    = 62  - 67    (60-61 = D-; 68-69=D+)
3rd Exam     15        F    = below 60
Homework     10
          In addition, students will have the opportunity to earn 1 to 2 extra credit points for a good (or great) oral presentation to the class.  Note:  The oral report is your fudge factor.  There will be no changing of grades if your total number of points comes “close”, but does not reach the next highest grade.

Psychology 418

Course Outline

DATES            TOPICS            READING

 1/19 - 1/21        Introduction/Nature of Science            Jackson, Ch. 1       

1/26 - 1/28        Getting Started on Research            Jackson, Ch. 2   

 2/2- 2/4            Understanding Variables            Jackson, Ch. 3

 2/9 - 2/11        Descriptive Methods & Surveys            Jackson, Ch. 4   

2/16 - 2/18        Writing a Paper                Jackson, Ch. 14*

 2/18            FIRST EXAMINATION

2/23 – 2/25        Centers, Variations, Z-scores             Jackson, Ch. 5

3/2 - 3/4            Correlations                Jackson, Ch. 6

3/9 - 3/11          Probability                 Class Notes

3/11            FIRST PAPER DUE

3/15 - 3/20        SPRING BREAK

3/23 - 3/25        Hypothesis Testing                Jackson, Ch. 7

3/30 - 4/1        Experimental Designs                Jackson, Ch. 8


4/6 - 4/8            One and Two Sample Designs            Jackson, Ch.  9

413 - 4/15        One Way Anovas                Jackson, Ch. 10

4/20- 4/22        Factorial Designs                Jackson, Ch. 11

4/27 - 4/29         Chi Square Statistic, etc.             Jackson, Ch. 13

5/4 – 5/6            Quasi Experimental Designs            Jackson, Ch. 12*

5/4 - 5/6        PRESENTATION OF GROUP EXPERIMENT 2           

 5/7            SECOND PAPER DUE

 5/13            THIRD EXAMINATION (9:00 - 11:00 AM)

*Chapters 12 and 14 will be discussed mainly in Lab meetings

PSY 394U • Fundmntls Early Perceptn & Cog

44180 • Spring 2010
Meets M 100pm-400pm SEA 1.332

Seminars in Cognitive and Perceptual Systems. Three lecture hours a week for one semester. May be repeated for credit when the topics vary. Prerequisite: Graduate standing and consent of instructor.

PSY 394U • Fundmntls Early Perceptn & Cog

44330 • Fall 2009
Meets M 100pm-400pm SEA 1.332

Seminars in Cognitive and Perceptual Systems. Three lecture hours a week for one semester. May be repeated for credit when the topics vary. Prerequisite: Graduate standing and consent of instructor.

PSY 418 • Statistics & Research Design-W

43045-43050 • Spring 2009
Meets TTH 930-1100 NOA 1.116

Students may not enroll in Psychology 418 more than twice. Survey of statistics, including central tendency, variability and inference, and scientific methodology used in psychological research. Three lecture hours and two discussion hours a week for one semester. Prerequisite: Psychology 301 with a grade of at least C, a major in psychology, and credit for one of the following: Mathematics 302, 303D, 305G, 408C, 408D, 408K (or 308K), 408L (or 308L), 408M (or 308M), 316.


Cashon C. & Cohen L.(2004) Beyond U-Shaped Development in Infants. Cognition and Development, 5, 59-80.

Cohen.L., Atkinson, D. & Chaput, H. (2004) A new program for obtaining and organizing data in infant perception and cognition studies, (Version 1.0).. University of Texas University of Texas

Cohen.L., Casasola, M. & Chiarello, E. (2003) Six-month-old infants' categorization of containment spatial relations. Child Development

Cashon C. & Cohen L. (2003) The construction, deconstruction, and reconstruction of infant face perception.. Nova Science.

Cohen.L. (2003) Unresolved issues in infant categorization. Oxford University Press. (pp 193-209).

Cohen.L. & Cashon, C. (2003) Infant perception and cognition. In R. Lerner, A. Easterbrooks, and J. Mistry (Eds.), Comprehensive handbook of psychology.Volume 6, Developmental Psychology. II. Infancy.(pp 65-89)   New York: Wiley and Sons.

Casasola M. & Cohen L. (2002) Infant categorization of containment, support and tight-fit spatial relationships. Developmental Science, 5, 247-264.

Cohen.L. & Chaput, H. (2002) Connectionist models of infant perceptual and cognitive development. Developmental Science, 5, 173-175.

Cohen.L. & Marks, K. (2002) How infants process addition and subtraction events. Developmental Science, 5, 186-201.

Cohen.L. & Chaput, H. (2001) A model of infant causal perception and its development. Proceedings of the Twenth-Third Annual Conference of the Cognitive Science Society,(pp182-187). Mahway: Lawrence Erlbaum Associates.

Career Overview

Dr. Cohen received his Ph.D. from UCLA in 1966. He then completed a post-doctoral fellowship at the University of Minnesota and in 1967 became an assistant professor in psychology at the University of Illinois. In 1979, he was recruited by The University of Texas and moved to Austin as a full professor in 1980. He continued in the Department of Psychology until the end of his phased retirement in 2010. During this period in 2001, he became an affiliated faculty member in both the Center for Perceptual Systems and the Artificial Intelligence Laboratory in the Department of Computer Science at The University of Texas. He also was a visiting professor at Beijing Normal University in the summer of 1985, in the Department of Psychology at the University of British Columbia in 1991, and in the Department of Cognitive Science at the University of California at San Diego in 1998.

Dr. Cohen’s primary line of research has been an investigation of infant perceptual, cognitive, and language development. This research interest actually began in the 1960s, when he was one of the top two or three researchers defining the field. The area really began in 1964 with Dr. Robert Fantz’ discovery that infants usually prefer to look at something novel than at something familiar. Dr. Cohen used that preference to develop a technique called habituation in which infants are repeatedly presented with the same stimulus until they get bored with it and decrease their looking at it. At that point, a novel stimulus is introduced and researchers see if infants increase their looking once again. If they do, one can conclude that the infants notice something differs between the old repeated item and the new item. Literally thousands of experiments have used this technique to examine everything from basic visual and auditory perception, to complex concept formation, categorization, music perception, and several aspects of language acquisition.

It soon became clear that in order to replicate and verify habituation findings from several different labs, the technique needed to be standardized. Dr. Cohen developed a simple computer program called “Habit” which included a variety of options to do just that, without hampering experimental variations and innovations. Dr. Cohen provided this program at no cost to infant research laboratories around the world, and “Habit” has now been used by more than 150 such laboratories. “Habit” has been successfully employed in hundreds, more likely thousands, of studies from his laboratory and others to investigate basic visual perception, auditory perception, categorization, concept formation, number perception, causal reasoning, facial perception, music perception, speech and sign language, and many other topics in both normal and handicapped infants. Dr. Cohen and his collaborators have produced over 250 articles, papers, book chapters, and four edited volumes on various aspects of infant perception and cognition.

Of course, an appropriate laboratory was needed to investigate these topics. Dr. Cohen and his colleagues designed one of the foremost infant research facilities here at The University of Texas. It included controlled testing rooms; a computerized database of infant names and addresses, shared by several investigators; parking spaces for parents next to the building; and a specialized ramp for strollers so mother and infant could enter the facility easily. It also included a waiting room, library, and office space for graduate and undergraduate assistants. In fact this laboratory has served as a model for other infant testing facilities around the world and several visiting investigators have attempted to emulate some or all of it.

Dr. Cohen also trained numerous graduate students who investigated some aspect of infant perceptual and/or cognitive development. Most of these students later became professors themselves at prestigious universities, including the University of Illinois, University of Virginia, Carnegie Mellon University, Indiana State University, University of California at Davis, Cornell University, Purdue University, University of Pittsburgh, University of Western Kentucky, University of Michigan, University of Iowa, and University of Louisville.

He also has collaborated with investigators from other laboratories, including the artificial intelligence group in computer science at The University of Texas. They are attempting to get robots to adapt and learn about their environment and are using learning principles Dr. Cohen discovered that human infants use. Currently, Dr. Cohen is collaborating with a group on a project at The University of Texas Health Science Center in Houston. They are attempting to discover specific ways infants with disabilities (spina bifida or cerebral palsy) differ cognitively from infants without those disabilities.

Another active collaboration has been with Professor Kim Plunkett at Oxford University on the effect of labels on infant categorization. This groundbreaking work combined three things: infant categorization, infant labeling, and connectionist modeling to predict whether infants would use the labels to form one or two separate categories of animals.

The artificial intelligence and modeling work has been important for two separate reasons. First, it has allowed researchers to make quantitative predictions about infant cognitive ability, predictions that have been confirmed; and second, it makes an important contribution to the longstanding nature-nurture debate. Some believe many cognitive and mathematical concepts are built-in. Given the enormous number of such concepts, this position clearly is untenable. On the other hand, if only a small number of connectionist learning principles need be built in, infants should be able to master a great many cognitive and linguistic concepts over time.

For many years Dr. Cohen has been a Fellow in the Association for Psychological Science and in the American Psychological Association. He spent six years on the National Institute for Child Health and Human Development Study Section evaluating developmental grants and chaired that Study Section for two years. He also chaired the International Society for Infant Studies, one of the most prestigious infant research societies, and was founding editor of the prestigious research journal, “Infancy” which is now in its 15th year of publication.


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