SECOND EDITION MATLAB for Behavioral Scientists David A.Rosenbaum. Jonathan Vaughan,Brad Wyble
Contents Preface ix Acknowledgements xi About the Authors 1 Introduction 1 2 Interacting With MATLAB 22 3 Matrices 38 4 Calculations 6 5 Contingencies 99 6 Input-Output 128 7 Data Types 8 Modules and Functions 182 9 Plots 10 Lines,Shapes,and Images 248 11 Animation and Sound 12 Enhanced User Interaction 13 Psychtoolbox 14 Debugging 355 15 Going On 370
vii Preface ix Acknowledgements xii About the Authors xiii 1 Introduction 1 2 Interacting With MATLAB 22 3 Matrices 38 4 Calculations 62 5 Contingencies 99 6 Input-Output 128 7 Data Types 156 8 Modules and Functions 182 9 Plots 208 10 Lines, Shapes, and Images 248 11 Animation and Sound 287 12 Enhanced User Interaction 304 13 Psychtoolbox 323 14 Debugging 355 15 Going On 370 Contents
vi Contents References 375 Commands Index 377 Name Index 381 Subject Index 382
viii Contents References 375 Commands Index 377 Name Index 381 Subject Index 382
Preface The first edition of MATLAB for Behavioral Scientists(published in 2007)was the result eeooeoeoe t write the ng stu ctive neuroscience,economics,a nd s mas much as scientists in other fields.They ohe able t n to do r the nally spe ing of granting agencies to pay other to program for them To give some examples a behavioral scientist-a behavioral economist.say-wishing to model decision making should be able to roll up her sleeves and observed and expected data in the way she prefers.A personality p in designing a new questionnaire requiring a special computer interface should be able to oursue that aim A svchotherapist wanting to model changing relations between mem- bers of a family should be able to characterize that process with custom-made animations that show network links with dynamically changing thicknesses and colors.growing and shrinking over time,if that's what she wants.A cognitive psychologist interested in setting up and conducting behavioral experiments should be able to create any kind of stimuli and response recording capabilities he or she cares to,not being limited by what's possible with off-the-shelf commercial products. This book is meant to help behavioral scientists(and especially students entering this field) to do these things.The authors of this book assume you have no prior familiarity with com- puter programming.and we assume you have no knowledge of mathematics beyond wha ble.our aim is to draw you in and help you feelcom in high sch he text is me at first seem foreign and maybe even scary. y as well a will appen b e.I es a tough hide to b ve you ha d has first but the med has s feel k to program.No one does! Programming needn't be unpleasant.however.The attitude to have is to keep an open mind about the value of mistakes.If you treat errors as windows for improvement,you will learn a lot.Availing yourself of that learning,when you see a program work and especially ix
ix Preface The first edition of MATLAB for Behavioral Scientists (published in 2007) was the result of a rebellious thought. The prevailing view before then was that most behavioral scientists shouldnÊt or couldnÊt write their own computer programs. This irked the first author, who decided to pursue the notion that all behavioral scientists, including students in the relevant fields (psychology, cognitive and affective neuroscience, economics, and so on), could and should learn to program for themselves. Behavioral scientists need to be able to program as much as scientists in other fields. They need to be able to program to do whatever they want, computationally speaking, without having to rely on the kindness of strangers or the largesse of granting agencies to pay others to program for them. To give some examples, a behavioral scientist·a behavioral economist, say·wishing to model decision making should be able to roll up her sleeves and graph data showing observed and expected data in the way she prefers. A personality psychologist interested in designing a new questionnaire requiring a special computer interface should be able to pursue that aim. A psychotherapist wanting to model changing relations between members of a family should be able to characterize that process with custom-made animations that show network links with dynamically changing thicknesses and colors, growing and shrinking over time, if thatÊs what she wants. A cognitive psychologist interested in setting up and conducting behavioral experiments should be able to create any kind of stimuli and response recording capabilities he or she cares to, not being limited by whatÊs possible with off-the-shelf commercial products. This book is meant to help behavioral scientists (and especially students entering this field) to do these things. The authors of this book assume you have no prior familiarity with computer programming, and we assume you have no knowledge of mathematics beyond what is generally learned in high school. The text is meant to be as friendly and encouraging as possible. Our aim is to draw you in and help you feel comfortable within a domain that may at first seem foreign and maybe even scary. Programming can be humbling. If you set out to learn to program, you should prepare yourself emotionally as well as intellectually for what will happen because you will be dealing with an unfeeling machine. It takes a tough hide to believe you have a program that does what you want, only to discover that the program doesnÊt run, generates unexpected results, or produces outputs that seem reasonable at first but then turn out to be wrong. Everyone who has programmed has gone through this, including the authors of this book, so donÊt feel like you need to be able to program perfectly. No one does! Programming neednÊt be unpleasant, however. The attitude to have is to keep an open mind about the value of mistakes. If you treat errors as windows for improvement, you will learn a lot. Availing yourself of that learning, when you see a program work and especially
Preface when it does something that,to your knowledge,has not been done before,can let you feel rightly proud of your achievement. There are many computer programming languages.Why is this book about MATLAB? MATLAB(short for Matrix Laboratory),is a commercial product of a company called The Math Works (Natick.Massachusetts).for which we authors do not work and have no com mercial connection.The following.therefore,can be taken as our honest opinion of their product:MATLAB is a simple yet powerful language for computer programming.It has an active community of users,engaged in many branches of science and engineering.One of M s m ractive igh-level comm lations with large as well as sm d fo ngpublic AB e collectio or the pr on of espo platf .runs o Cs.Ma ng ntist vith in oth is have therefor MATLAB ing to the hea alth an it is to learn matlab in the futu e.You will be art of thatacti ou choose to dive into the material provided here How did it come to n ss that there is a second edition of this book?As is always true of a second edition,its predecessor was successful enough to keep the work alive.but changes in the field suggested a face-lift was needed.Among the needed changes was the appear- ance of other MATLAB books for psychologists and neuroscientists(Fine Boynton. 2013:Madan,2014:Wallisch et al.2009).which are welcome additions.though they are different in style,tone,level of coverage,and organization from the first edition of this book(but not so perfect,in our view,that they obviate this second edition). As the author of the first edition (Rosenbaum,2007)contemplated the second edition,he realized that the process of revising and updating the book would benefit from the involve- ment of his long-time friend and collaborator,Jonathan Vaughan,the James L.Ferguson Professor of Psychology and Neuroscience at Hamilton College.Jon has decades of experi- ence with computer programming.He has served as the editor of Behavior Research Meth wed publication of the Psychonomic Society irst a hor bas AB from Jon.He continued to leamn from Jon in an【 map out the ways the e sec ong th ag o we (1)All kn errors in the e firstediti would b cted more gging;G ic AB (4 blems woulda with do n the hook's com/780415535946)rather than in the back of the book to allow for mor pdating of the nd additio eds and 5h ould he a tutorial on designing gra GUIs,which enable a user to interact with a program using g within MATLAB:(6)there would be a tutorial in designing experiments using Psychtool- box,a freely available MATLAB toolbox that is specifically geared to behavioral science
x Preface when it does something that, to your knowledge, has not been done before, can let you feel rightly proud of your achievement. There are many computer programming languages. Why is this book about MATLAB? MATLAB (short for Matrix Laboratory), is a commercial product of a company called The MathWorks (Natick, Massachusetts), for which we authors do not work and have no commercial connection. The following, therefore, can be taken as our honest opinion of their product: MATLAB is a simple yet powerful language for computer programming. It has an active community of users, engaged in many branches of science and engineering. One of MATLABÊs most attractive features is that it offers high-level commands for performing calculations with large as well as small data sets and for generating publication-quality graphics. Another attraction of MATLAB is that it allows for the presentation of stimuli and the collection of responses with precise timing. Yet another attraction is that MATLAB is platform-independent. It runs on PCs, Macs, and Linux machines. For these and other reasons, MATLAB is a very good language for behavioral scientists. A growing number of behavioral scientists, along with neuroscientists, engineers, and investigators in other disciplines, have therefore chosen to learn MATLAB. Owing to the health and vitality of the MATLAB programming community, it is likely that more and more people will want to learn MATLAB in the future. You will be part of that active community if you choose to dive into the material provided here. How did it come to pass that there is a second edition of this book? As is always true of a second edition, its predecessor was successful enough to keep the work alive, but changes in the field suggested a face-lift was needed. Among the needed changes was the appearance of other MATLAB books for psychologists and neuroscientists (Fine & Boynton, 2013; Madan, 2014; Wallisch et al., 2009), which are welcome additions, though they are different in style, tone, level of coverage, and organization from the first edition of this book (but not so perfect, in our view, that they obviate this second edition). As the author of the first edition (Rosenbaum, 2007) contemplated the second edition, he realized that the process of revising and updating the book would benefit from the involvement of his long-time friend and collaborator, Jonathan Vaughan, the James L. Ferguson Professor of Psychology and Neuroscience at Hamilton College. Jon has decades of experience with computer programming. He has served as the editor of Behavior Research Methods, Instruments, & Computers , a peer-reviewed publication of the Psychonomic Society. The first author basically learned MATLAB from Jon. He continued to learn from Jon in preparing this second edition. When Jon agreed to join in, he and David began to map out the ways the second edition would differ from the first. Among the things they agreed to were the following: (1) All known errors in the first edition would be corrected; (2) more would be said about debugging; (3) more problems would be given, including problems that would help students confront very basic issues in the rudiments of MATLAB; (4) solutions to selected problems would appear with downloadable code on the bookÊs new website ( www.rout ledge.com/9780415535946 ) rather than in the back of the book to allow for more extensive code, updating of the programs if necessary, and addition of new programs as needs and curiosities arose; (5) there would be a tutorial on designing Graphical User Interfaces, or GUIs, which enable a user to interact with a program using graphics to run experiments within MATLAB; (6) there would be a tutorial in designing experiments using Psychtoolbox, a freely available MATLAB toolbox that is specifically geared to behavioral science
Preface xi be entation. ssible.with mo rial slowly and asa wernng a way as possible,with more specia ecialized topics comin as the chanters nued use of a style that worked well heforeintroducing a new problem or challer e presenting associated code and then presenting the output.In addition.as in the first edition.each chapter starts with a list of things to be done followed by commands that get them done.These start-of-chapter lists let you use the book as a reference once you understand the basics of MATLAB.Thus. after you have worked your way through the book.you will be able to turn to a section and quickly get the detailed information you need to complete the programming task you are undertaking.All the commands are listed as well in a single Command Index near the back of the book.another innovation of the second edition relative to the first. Another way we have made the text as user-friendly as possible is to update the website fo this book.On this site.you will be able to find and copy the programs and program outputs in this volume.The outputs on the website have color,motion,and sound,whereas those modalities are absent from the printed edition. As shown in the list o TLA the second edition ha a chapte on Psychtoolbo Thi L ing be ora Jon simply b or thei ppened.h wever,that in the Pen ep d Jon and Da nd.to their great d to prepare a chapter for th Brad'rea,the domain of which,it hap Psychtoolbox is d the st With his r scie was a computer science major as an under rad and did re arch in uter sei ence labs after completing his PhD at Haryard he proved to be a wonderful addition to the team His involvement in the book was limited to the one chapter he prepared,plus his review of this Preface,as per the agreement he made with Jon and David.Any errors in the book. then outside of the psychtoolbox chapter and the preface are not due to brad by the same token.any errors in the psychtoolbox chapter and in the preface are as much lon's and David's fault as they are,or might be,Brad's.In general,any mistakes rest squarely with Jon and David.or most especially David.who.after having had several vears to mull over the transition from the first edition to the second,should have gotten things right by now! The last thing we want to say in this preface echoes what we say in the main text about responsiveness to feedback.It is fine to be open to feedback from a computer,as we urge you to be,but it is also good to be open to feedback from people.If you spot something tha you think could be better,please let us know.If you have sugges ons for things to includ in a future dition,give us ose want he Ip with your prograr cannot s anding on th at last p ou with us.you can e of our e-mai this
Preface xi research; and (7) special tricks and new functions, developed or discovered since 2007, would be featured, including several developed by the authors to solve sometimes thorny problems that arise in data collection and data presentation. In preparing the second edition, Jon and David made these changes while retaining the main organization of the bookÊs first edition. As before, readers are ushered to the material slowly and in as a welcoming a way as possible, with more specialized topics coming as the chapters continue. Also as in the first edition, there is continued use of a style that worked well before·introducing a new problem or challenge, presenting associated code, and then presenting the output. In addition, as in the first edition, each chapter starts with a list of things to be done followed by commands that get them done. These start-of-chapter lists let you use the book as a reference once you understand the basics of MATLAB. Thus, after you have worked your way through the book, you will be able to turn to a section and quickly get the detailed information you need to complete the programming task you are undertaking. All the commands are listed as well in a single Command Index near the back of the book, another innovation of the second edition relative to the first. Another way we have made the text as user-friendly as possible is to update the website for this book. On this site, you will be able to find and copy the programs and program outputs in this volume. The outputs on the website have color, motion, and sound, whereas those modalities are absent from the printed edition. As shown in the list of new features, the second edition has a chapter on Psychtoolbox. This is a free, popular, MATLAB-based toolbox for running behavioral experiments. Neither Jon nor David had used Psychtoolbox before, simply because it wasnÊt essential for their work. It happened, however, that Brad Wyble, a newly hired faculty member in the Penn State Psychology Department (the department where David works), had extensive experience with Psychtoolbox. Jon and David invited Brad to prepare a chapter for the book on Psychtoolbox, and, to their great satisfaction, he agreed. BradÊs area of expertise is vision, the domain of behavioral science in which, it happens, Psychtoolbox is used the most. With his extensive background in computer science·Brad was a computer science major as an undergrad and did research in computer science labs after completing his PhD at Harvard·he proved to be a wonderful addition to the team. His involvement in the book was limited to the one chapter he prepared, plus his review of this Preface, as per the agreement he made with Jon and David. Any errors in the book, then, outside of the Psychtoolbox chapter and the Preface are not due to Brad. By the same token, any errors in the Psychtoolbox chapter and in the Preface are as much JonÊs and DavidÊs fault as they are, or might be, BradÊs. In general, any mistakes rest squarely with Jon and David, or most especially David, who, after having had several years to mull over the transition from the first edition to the second, should have gotten things right by now! The last thing we want to say in this preface echoes what we say in the main text about responsiveness to feedback. It is fine to be open to feedback from a computer , as we urge you to be, but it is also good to be open to feedback from people . If you spot something that you think could be better, please let us know. If you have suggestions for things to include in a future edition, give us those suggestions. If you want help with your programming, we cannot serve as consultants to you. We appreciate understanding on that last point. To get in touch with us, you can use one or more of our e-mail addresses: dar12@psu.edu, jaughan@ hamilton.edu, or bpw10@psu.edu. We hope you will find this book useful
Acknowledgements praise and thanks for their contributions.direct and indirec There are others who deservdnt who took the MATLAB o First.we express our app by David at Penn State and by Jon at Hamilton,and who also were exposed to MATLAB by Brad.Teaching these students helped us see which programming concepts are transpar- ent and which are less so. Several students in our classes and in our labs played especially important roles in helping us hone our MATLAB instruction.We thank Penn State students Max Bay,Katie Chap- man,Chase Coelho,Rajal Cohen,Samantha Debes,Jeff Eder,Jason Gullifer,Lanyun Gong.Derek Henig.Joe Santamaria,Garrett Swan,Matt Walsh,and Robrecht van der Wel. We thank Hamilton College students Deborah Barany.Julia Brandt,Hallie Brown,Drew Linsley.Ramya Ramnath.and Anthony Sali.Others who provided valuable feedback are Debra Boutin.Gillian Dale,Mike Frederick,Michael Romano,and Doug Weldon.Mario Kleiner provided helpful information about Psychtoolbox. We also wish to thank the reviewers who provided feedback on the revision plan:Si K:Aln Pajal.Universityof ouhppl.SA This book was competed whle theist sabbatical in Los dusc Angeles. at UCLA hip from th ble's resea Is supporte tim of thi nt BCS #1331073 I the N upp and the natio has vid's.We all this suppor not to mention the support of the institu tions that have paid ou alar We also wish to express our thanks to paul dukes at Psychology Press/Tavlor francis mental in ing the door for the se nd edition of the book paul called on his colleague debra riegert to work with us to br ing the work to completion Debr was responsive and helpful at every stage.We appreciate her help as well as the further assistance of Angela Halliday at Routledge/Taylor Francis,who helped with the book's and website's production. xii
xii Acknowledgements There are others who deserve praise and thanks for their contributions, direct and indirect. First, we express our appreciation to the students who took the MATLAB courses offered by David at Penn State and by Jon at Hamilton, and who also were exposed to MATLAB by Brad. Teaching these students helped us see which programming concepts are transparent and which are less so. Several students in our classes and in our labs played especially important roles in helping us hone our MATLAB instruction. We thank Penn State students Max Bay, Katie Chapman, Chase Coelho, Rajal Cohen, Samantha Debes, Jeff Eder, Jason Gullifer, Lanyun Gong, Derek Henig, Joe Santamaria, Garrett Swan, Matt Walsh, and Robrecht van der Wel. We thank Hamilton College students Deborah Barany, Julia Brandt, Hallie Brown, Drew Linsley, Ramya Ramnath, and Anthony Sali. Others who provided valuable feedback are Debra Boutin, Gillian Dale, Mike Frederick, Michael Romano, and Doug Weldon. Mario Kleiner provided helpful information about Psychtoolbox. We also wish to thank the reviewers who provided feedback on the revision plan: Simon Farrell, University of Bristol, UK; Alen Hajnal, University of Southern Mississippi, USA; and an anonymous reviewer. This book was completed while the first author was on sabbatical in Los Angeles, at UCLA and USC, where he was supported in part by a fellowship from the John Simon Guggenheim Memorial Foundation. Brad WybleÊs research was supported at the time of this writing by NSF grant BCS #1331073. JonÊs research has been supported by grants from the National Science Foundation and the National Institutes of Health, as has DavidÊs. We all appreciate this support, not to mention the support of the institutions that have paid our salaries. We also wish to express our thanks to Paul Dukes at Psychology Press/Taylor & Francis, who was instrumental in opening the door for the second edition of the book. Paul called on his colleague, Debra Riegert, to work with us to bring the work to completion. Debra was responsive and helpful at every stage. We appreciate her help as well as the further assistance of Angela Halliday at Routledge/Taylor & Francis, who helped with the bookÊs and websiteÊs production
About the Authors David A.Rosenbaum is a cognitive psychologist whose main interests are human per ception and performance.His main research contribu chold ogy and motor cor aum atten d pu n B 197 sity(P 1 98 niversity of 1994.Heha ce1994, Amherst(19 ennsylvani h en at p in2000 (19731976 enc ad h Co (1985-1990),and a National Institutes of Health Research Scie tist develo 1992-1997.His h nte fro m the nati al oundation SE)and the nat rants fr om the Dutch.Fr ch.and German equivalents of NSF Rosenbaum is a Fellow of the American Association for the Advancement of Science,the American Psychological Association,the American Psycho- logical society and the society of experimental psychologists He served as editor of Journal of Experimental Psvchology:Human Perception and performance (a publication of the american psychological association)from 2000 to 2005.He was awarded a gug. genheim Foundation Fellowship in 2012 for the 2013-2014 academic year.Besides being the author of the first edition of this book,David is the author of a textbook on motor control [Rosenbaum.2010]and the author of a book applying Darwin's theory of natural selection to cognitive psychology Rosenbaum,2013. Jonathan Vaughan is a broadly trained experimental psychologist(B.A.,Swarthmore College. 196 -1966:Ph.D.Brown University.1966-1970)whose research interests focus on the planning and execution of motor actions,eye movements and attentional processe human and anima I le rning.and cognitive neuropsychology He taught at Hamiltor College since 19 His work with Dav senbaum an IRuud G.J. ated under an ARE NINDS. nas pr els of re ing,grasp 0 the Nom. and NIMH. Publishe more tha ven n an I ial of Ps the ps founded the Psvchonomie Society's Archive uli and Data data and stimu ns that has served as an importan resource for res in the field. xi
xiii About the Authors David A. Rosenbaum is a cognitive psychologist whose main interests are human perception and performance. His main research contribution has been joining cognitive psychology and motor control. Rosenbaum attended public schools in Philadelphia and then attended Swarthmore College (B.A., 1970ă1973) and Stanford University (Ph.D., 1973ă 1977). He worked at Bell Laboratories (1977ă1981), Hampshire College (1981ă1987), and the University of Massachusetts, Amherst (1987ă1994). He has been at Pennsylvania State University since 1994, where he was named Distinguished Professor of Psychology in 2000. Rosenbaum was a recipient of a National Science Foundation Graduate Fellowship (1973ă1976), a National Institutes of Health Research Career Development Award (1985ă1990), and a National Institutes of Health Research Scientist Development Award (1992ă1997). His work been supported by grants from the National Science Foundation (NSF) and the National Institutes of Health, as well as grants from the Dutch, French, and German equivalents of NSF. Rosenbaum is a Fellow of the American Association for the Advancement of Science, the American Psychological Association, the American Psychological Society, and the Society of Experimental Psychologists. He served as Editor of Journal of Experimental Psychology: Human Perception and Performance (a publication of the American Psychological Association) from 2000 to 2005. He was awarded a Guggenheim Foundation Fellowship in 2012 for the 2013ă2014 academic year. Besides being the author of the first edition of this book, David is the author of a textbook on motor control [Rosenbaum, 2010] and the author of a book applying DarwinÊs theory of natural selection to cognitive psychology [Rosenbaum, 2013]. Jonathan Vaughan is a broadly trained experimental psychologist (B.A., Swarthmore College, 1962ă1966; Ph.D., Brown University, 1966ă1970) whose research interests focus on the planning and execution of motor actions, eye movements and attentional processes, human and animal learning, and cognitive neuropsychology. He has taught at Hamilton College since 1971. His work with David Rosenbaum and Ruud G. J. Meulenbroek, initiated under an AREA grant from the NINDS, has produced computational models of reaching, grasping, tapping, and manual circumvention of obstacles. Other research support has come from the NSF and NIMH. Vaughan has published more than 60 journal articles and book chapters, and given more than 100 research presentations, many in collaboration with Hamilton undergraduates. He has contributed in many ways to computer applications in psychological research, including tutorial materials for the use of PsyScope and SPSS. He edited the Psychonomic SocietyÊs international quarterly, Behavior Research Methods, Instruments, and Computers [1994ă2004] and founded the Psychonomic SocietyÊs Archive of Norms, Stimuli, and Data, an online repository of computer programs, data, and stimulus norms that has served as an important resource for researchers in the field
xiv About the Authors Brad Wyble studies attention,perception,and memory.He attended public schools in Lan- caster,Pennsylvania,after which he obtained a B.A.in computer science from Brandeis University(1991-1995)and a Ph.D.in psychology from Harvard University(1996-2003). He was a postdoctoral fellow at the University of Kent in Canterbury,England(2003- 2007).University College,London(2007),and MIT(2007-2009).He was subsequently an assistant professor at Syracuse University (2009-2012)and is now an assistant professor at Pennsylvania State University in the Department of Psychology.Wyble was a recipient of a National s ience Foundation Graduate Fellowship(1997 (2001-2002),and he has been supported by grants from the Science Foundatior the Office of Na and the Nation Institutes of Health.He serves as a ing edito or the a Perception and Perfor mance,and as an joum
xiv About the Authors Brad Wyble studies attention, perception, and memory. He attended public schools in Lancaster, Pennsylvania, after which he obtained a B.A. in computer science from Brandeis University (1991ă1995) and a Ph.D. in psychology from Harvard University (1996ă2003). He was a postdoctoral fellow at the University of Kent in Canterbury, England (2003ă 2007), University College, London (2007), and MIT (2007ă2009). He was subsequently an assistant professor at Syracuse University (2009ă2012) and is now an assistant professor at Pennsylvania State University in the Department of Psychology. Wyble was a recipient of a National Science Foundation Graduate Fellowship (1997ă2000), he was a Sackler Fellow (2001ă2002), and he has been supported by grants from the National Science Foundation, the Office of Naval Research, and the National Institutes of Health. He serves as a consulting editor for the Journal of Experimental Psychology: Human Perception and Performance , and as an associate editor for the journal Frontiers in Cognition
1.Introduction This chapter covers the following topics: 11 Getting oriented 15 Deciding if a program is needed and whether you should write it e outhydo orking increme 110 Writing concise programs 12 Writing clear programs ng con program the website ass heerifibogtaeoeganized 1.15 Obtaining and installing MATLAB 1.16 Acknowledging limits 1.1 Getting Oriented Computers are vital in every branch of science today,and behavioral science is no excep- tion.When behavioral scientists use computers to obtain responses in questionnaires.pres- ent visual stimuli,display brain images,generate data graphs,or write manuscripts,their ability to make efficient progress in their research depends largely on their ability to use computers effectively. Many specialized computer packages let behavioral scientists do their work,and each one takes some time to learn.It is useful to know how to use these specialized packages,but it is nal3tocciderthepoabyofleamimehowopoeamforJyog The reason s that ompu d knowing how to gene Suppose,for example.that I: with differe nd P ly,it is write the to vio aphs of obtained or theo in a erate the graphs quickly and easily.however you please,not just as stipulated by an existing graphics package. The computer language introduced here.MATLAB.provides you with these capabilities. MATLAB is available from The MathWorks(www.mathworks.com),a company with which
1 1. Introduction This chapter covers the following topics: 1.1 Getting oriented 1.2 Getting an overview of this book 1.3 Understanding computer architecture 1.4 Programming principles 1.5 Deciding if a program is needed and whether you should write it 1.6 Being as clear as possible about what your program should do 1.7 Working incrementally 1.8 Being open to negative feedback 1.9 Programming with a friend 1.10 Writing concise programs 1.11 Writing clear programs 1.12 Writing correct programs 1.13 Understanding how the chapters of this book are organized 1.14 Using the website associated with this book 1.15 Obtaining and installing MATLAB 1.16 Acknowledging limits 1.1 Getting Oriented Computers are vital in every branch of science today, and behavioral science is no exception. When behavioral scientists use computers to obtain responses in questionnaires, present visual stimuli, display brain images, generate data graphs, or write manuscripts, their ability to make efficient progress in their research depends largely on their ability to use computers effectively. Many specialized computer packages let behavioral scientists do their work, and each one takes some time to learn. It is useful to know how to use these specialized packages, but it is also tantalizing to consider the possibility of learning how to program for yourself. The reason is that all specialized computer packages rely on underlying code, and knowing how to generate such code yourself can allow you to be self-sufficient or nearly so in your own research. Suppose, for example, that you want to develop a mathematical model of some cognitive process. It is convenient to be able to write a program that lets you explore the mathematical model freely, seeing the results obtained with different equations, different parameter values, and so on. Similarly, to analyze data in ways that would be cumbersome with existing spreadsheet applications, it is refreshing to be able to write the analysis program to your own specifications. For example, to view graphs of obtained or theoretical data in a variety of forms, it is useful to be able to generate the graphs quickly and easily, however you please, not just as stipulated by an existing graphics package. The computer language introduced here, MATLAB, provides you with these capabilities. MATLAB is available from The MathWorks ( www.mathworks.com ), a company with which