Avian Visual Cognition

Birds, Brains, and Bits 
Robert G. Cook
Department of Psychology, Tufts University

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 Welcome to the brave new world of electronic publishing. Avian Visual Cognition provides a comprehensive and systematic survey of one area of modern comparative research and represents the first multimedia cyberbook about animal cognition available in an electronic format. Because of the Internet, we are in the midst of an information revolution that is transforming virtually every aspect of the world, fundamentally changing what we mean by information and how it is shared. Science is no more immune to this trend than any other human endeavor. In fact, it can be argued that scientific information is ideally suited to this particular medium. This cyberbook is an attempt to advance this activity and provide a new direction to the public dissemination of scientific information in my area of psychology.

Another function of this cyberbook is to reflect a second revolution as well. Over the last several decades, scientific thinking has substantially shifted about how animals process information for the purpose of their survival. This modern comparative study of animal cognition now seeks to understand how animals encode, transform, compute, and manipulate symbolic representations of the world's spatial, temporal, and causal texture in order to adaptively organize their behavior. It represents an exciting synthesis of animal learning, cognitive science, and behavioral ecology. This change has enormously expanded the breadth, nature, and sophistication of the psychological issues studied in animals in comparison to the earlier approaches of the last century. This new approach attempts to understand cognition and information processing across the entire spectrum of animals, not just humans and other mammals. Its objective is to create a general theory of cognition, behavior, and how they evolved, so as to explain the shared and distinctive patterns of animal behavior, their function, and underlying generative mechanisms.

Other scientific communities and the general public are generally unaware of this theoretical shift, however. This is unfortunate because the scientific information collected and techniques developed over the last several decades offer enormous value to those interested in understanding, for instance, the neural mechanisms of cognition and behavior or its computational nature. This cyberbook attempts to remedy this situation by using the vast distribution and information resources of the Internet.

But why birds? Birds are highly visual and mobile animals, and vision's unmistakable importance to these creatures is reflected in the huge relative size of their eyes and the considerable portion of their brains devoted to processing visual information. Given their highly visual orientation, birds therefore comprise an important group to compare with mammals, the other major class of warm-blooded, highly mobile, visually-oriented animals to have evolved. For instance, when we open our eyes, we see an immediate visual world of stable and meaningful objects that we detect, grasp, catch, and avoid effortlessly. Despite the apparent ease by which we do this, vision scientists have determined that the cognitive processes needed for these visual feats require considerable computational prowess. Birds similarly behave as if they perceive and act upon a world full of objects. Yet due to the demands of flight, birds have been under strong evolutionary pressures for the last 200 million years to keep their overall size to a minimum. While indeed a large portion of the avian CNS is devoted to visual processing, the fundamental problem remains that the bird brain is just a bare fraction in size to our own. It is this extraordinary mixture of visual competence and small size that makes the study of birds important to our understanding of the general mechanisms of visual cognition. They provide essential comparative information about these  processes in a small, visually-sophisticated, non-mammalian, biological system. Besides these scientific questions, they also provide practical information. Just as birds were once the inspiration and key to developing the technology of flight, they continue to provide significant encouragement that workable small visual protheses for the visually impaired might be developed in the near future, for instance.

This cyberbook brings together 31 of the top international scientists working in the area of comparative cognition to create a widely available summary of current advances in our knowledge about visual cognition in birds. Each chapter highlights a different aspect of the basic processes within the general area of visual cognition and action. Although more a device of convenience, since the vast majority of these processes operate in parallel and are highly interconnected, the chapters of the book are more or less organized by the increasing complexity of the processes and behaviors presumably involved in each topic. 

The first chapter by Husband & Shimizu provides a phylogenetic context for vision in these animals and provides some basic information about the neural organization of the avian visual system. Like mammals, birds have two major visual pathways. In laterally-eyed birds like pigeons, the relative importance of these pathways to vision is reversed. This intriguing role reversal and other telencephalic differences in birds suggest that neural organizations besides the primate geniculo-striate pathway can also rapidly construct dynamic visual representations. The second chapter by Balsam brings into this mix the role of ontogenetic factors, by examining the role of development and learning in the visually-controlled pecking behavior in ring doves. The next three chapters by Cook, Kirkpatrick, and Young & Wasserman examine some of the basic perceptual and discriminative processes involved when birds discriminate complex stimuli, such as multi-element arrays and objects. The following two chapters, by Sutton & Roberts and Shimp, Herbranson, & Fremouw, look in more detail at the general issue of stimulus selection and the role of attention in how birds process compound stimuli composed of independent dimensions (see also P. Blough’s chapter). Visual similarity is one of the most fundamental topics in psychology and it forms the focus of the next chapter by D. Blough. Interestingly, in complete disparity to its probable importance to birds, only the chapter by Dittrich & Lea is devoted to the visual processing and discrimination of motion (see the last section of my chapter, too). The next group of three chapters outlines advances in our understanding the mechanisms of learning and memory in birds. The chapter by Wright describes how pigeons use different processing strategies in learning the same type of discrimination. Grant & Kelly’s chapter reviews the mechanisms of short-term retention in discrimination learning in pigeons, while Chase & Heinemann’s considers the role of long-term exemplar memory. The mechanisms underlying visual categorization form the core of the next two chapters by Huber and Urcuioli (see also Young & Wasserman’s chapter). Huber’s chapter provides a review of theories and recent data in this area, while Urcuioli’s looks at how experience also acts to glue stimuli together into larger groups.

Whereas these earlier chapters focus more on the processes of visual cognition, the latter chapters examine how this visual information is involved in other aspects of bird behavior. Cheng & Spetch’s chapter reviews their research on how visual landmarks control spatial navigation. Emmerton’s chapter is focused on the issue of number and counting. P. Blough’s looks at how visual search and attention are employed in the daily task of finding food. While humans often admire the beautiful plumage of birds, this coloration is key to their sexual success. The chapter by Akins & Burns’ reviews their recent work on the visual control of this important behavior. The chapter by Terrace examines at how birds understand and code sequential visual information and how this processing directly compares with those employed by humans and monkeys. Finally, the chapter by Zentall & Akins reviews how the simple visual observation of other animals can also change the observer's behavior.

I personally want to thank all of the contributors to this cyberbook. Because it is outside the current bounds of traditional publication, they have all taken a risk by contributing to this digital project, and I am grateful for their efforts in making this book come to life. Their participation shows an insightful recognition of how the Internet is changing the face of scientific communication. Given this, the last few sections of this introduction offer some brief observations about the digital format and presentation of the information in this book.

Science is a nonprofit (at least for scientists), fast moving, social activity. It advances through the combination of experimental efforts by individual scientists and the group dissemination of this information to other scientists and interested people. As scientists, we have traditionally given away our data and texts so that others can share in our collected and collective knowledge to advance our science. This cyberbook keeps with that tradition by being completely free. In the past, our freely given manuscripts have had several gateways in their travels from pen to printed page. One of these gateways revolved around those who could afford a printing press. With the Internet, scientific information is no longer held hostage by this publishing constraint as virtually anyone can own a "printing press". This new freedom releases scientific writing from publishers interested in profit. This change can be seen in this type of book and in the increasing number of research archives and e-journals that have come on-line in just the last few years.

A second gateway in traditional scientific publication has been the process of peer review. Peer review is science’s quality control. In this process, other scientists review the content of a paper and make recommendations to journal editors about its merits. In my opinion, this process is still an absolutely essential one and it should not be replaced by the advent of electronic publishing, despite some claims to the contrary. Given this position, how should one, or perhaps more importantly tenure and promotion committees, view the current book and its contributions. Its contents have undergone the same kind of editorial review of any typical edited print volume, with extensive comments provided to the authors and acceptable revisions prepared in return. However, the scrutiny of invited chapters is never the same as for unsolicited manuscripts to a top-flight journal (nor should it be). As such, these chapters should be viewed in exactly the same light as any contributed effort to an edited print volume. In fact, I would argue they should be given slightly more weight because of their innovative nature and the value that has been added to these digital chapters. What is this added value?

Now I love books -- old books, new books, it doesn’t matter. I love their look, their feel in my hands, the excited turn of each page, even their new or musty smell. Alas, printed pages do have limitations, ones that all of us have increasingly encountered in dealing with traditional print journals. For instance, it is very expensive to print color figures, despite the clear documentation that it enhances the visual encoding and retention of information. Color stimuli or large sets of stimuli are similarly impossible to publish, either because of price or page limitations (the size and scope of this book tells you that electronic pages are economical). Neither does the printed page handle dynamic content very well. Thus animated examples of testing procedures, their relative timing, or video clips of the animals are impossible to show a reader. Printed pages cannot directly hyperlink you to relative or ancillary material on demand. It is difficult to include your software or provide interactive demonstrations of the experiments. Yet all of these things enhance a reader’s understanding of an author's work. With increasing ease, the web can do all of these things. In fact, one reason that handheld e-books have not been very successful is because they have only attempted to replace the printed page with an electronic one that does not digitally enhance the reading experience. In developing this cyberbook, I have strived to bring this value to its scientific content by adding multimedia material whenever possible, going beyond that provided in traditional scientific volumes and journals.

As a result, you will find throughout the book different types of new content that will hopefully add to your understanding of each chapter. Some of these include: videos of the animals performing in the different experiments, interactive demonstrations of the procedures described in the chapters, numerous supporting color figures and photographs, sets of entire stimuli tested with the birds, animated illustrations of various theoretical ideas, and on-demand references that connect to public databases whenever possible. Lastly, as you go through the various chapters you will see several distinct styles. These different forms evolved over the course of the project and represent the contrasting ways authors wanted to present and organize their information. I have purposely not forced them into a standard form, in part because of my own ignorance about what is the optimal way to communicate over this new medium. For this, we can turn to natural selection. Diversity is generally a good thing early in an evolutionary cycle. It allows the various designs to compete and the ones best suited to an environment to reproduce most successfully. I assume the same process will operate on the best ways to communicate scientific information over web. 

Lastly, I would like to thank all of the wonderful and talented Tufts students who helped to make this book possible -- Deborah Levison, Jon Baker, Alyssa Heumann, Sarah Gillett, Aaron Blaisdell, Shelley Roberts, Valerie Parkison, Liz Kosseff, Brian Korb, and Danh Luu. I also want to especially thank the Provost of Tufts University, Sol Gittleman, for his intellectual and financial support for this project. Further support for this project was also provided by the National Science Foundation. NSF is a critical agency to the future of animal behavior, and I am very thankful for the long-term support of my past and current research on avian visual cognition by this organization. Finally, I very much want to thank my loving wife, Sher, for her continuous support and encouragement throughout this project. This book is dedicated to Sher and my two children, Allie and Matt. Birds are great, but young mammals are the very best.