Subjective Time: The Philosophy, Psychology and Neuroscience of Temporality
by Valtteri Arstila and Dan Lloyd, Editors
The MIT Press, Cambridge, London, 2014
688 pp., illus. 88 b/w. Trade, $65.00
Reviewed by Vaibhav Tyagi
Marie Curie Fellow 'CogNovo'
Plymouth University, Cognition Institute
From Albert Einstein to Stephen Hawking, many physicists have pondered the question Ð What is time? Einstein's following quote on time gives us a clear picture of what time meant to him. He said Ð "The only reason for time is so that everything doesn't happen at once". Temporality has been a fascinating field of research among philosophers, artists and scientists alike. Subjective Time: The Philosophy, Psychology and Neuroscience of Temporality by Valtteri Arstila and Dan Lloyd provides a comprehensive overview that attempts to address one of the most important questions in temporality research Ð What is the relationship between objective or 'true' time and its subjective counterpart as we perceive it. The importance of this question lies in its reach toward a better understanding of not just our perception of time but also to understanding the processes involved in our perception of the physical reality of the world.
The book is a complication of reprinted published materials and newly commissioned chapters and has been divided into separate sections, each dealing with a unique aspect of the study of subjective time. Section I begins with a brief history of modern interest in subjective time. Excerpts from the works of eminent philosophers William James (1842-1910) and Edmund Husserl (1859-1938) are presented systematically in the first few chapters. In his book The Principles of Psychology James studies mind as a continuous stream of thought, with characters such as thoughts being personal, dynamic, picky and continuous and independent of self. He calls the dynamic nature of consciousness as a 'stream of thought' or 'subjective life'. He further asserts that attention helps us 'pick' or 'choose' interesting objects from this stream. In The Principles of Psychology James explicitly addresses conceptualization and perception of time. The lingering of old objects and the incomings of new, he says, are "the germs of memory and expectations" without which consciousness can't be called a stream. According to James, the present has a fixed duration and anything before it is obvious past and anything after, the unknown future, which he termed the 'specious present'. He makes references to the great German philosopher Wilhelm Wundt and his student Georg Dietze's experiment and calculates the duration of the perceptible specious present to be around 3.6 to 6 seconds. He further quotes experimental data and suggests that we have a sense of what is called an indifference point where subjective time matches the real time and away from which (in both directions) errors increase in size. He thus concludes that our sense of time is so subjective that it (like any other senses) is biased by contrast Ð a time interval 'feels' shorter if preceded by a longer time interval and vice versa.
Following James's excerpts, philosopher and psychologist Holly Andersen takes the reader on a journey of the study of temporal experience and the development of the idea of what James referred to as the 'specious present' from 1690 to the 1900s. The following chapter presents Husserl's account of his conceptions of time according to which, as we move along the flow of consciousness, the shading-off of a primary event is presented as fading or dying content. Husserl goes on to claim that this shading-off is not self sufficient to create the perception of time. It is the interpretation of this shading-off that gives us a perception of a degree of temporal departure. This is further elaborated in this section by describing concepts of retentions (shading-off) and protentions in constitution of the perception of past, present and future.
Section II of the book is dedicated to contemporary philosophies of temporality. Chapter 5 revisits Husserl's original ideas and the concepts of protention-primal impression-retention in the light of recent arguments by philosophers and cognitive neuroscientists that perception is enactive or action-oriented. Barry Dainton (philosopher and acclaimed author of books on the topics of self, consciousness and time) in 'The phenomenal continuum' talks about the temporal experience and perception of continuity. He explains the basics of two opposing theories of the experience of change Ð extensionalist & retentionalist. Dainton provides support in favor of the extensionalist explanation of overlapping specious presents while criticizing the retentionalist explanation on the grounds of its complexity and incompatibility with the limits of neural processing. The final chapter of this section deals with the relation between the temporal structure of experience and the temporal structure of objects of experience. It defends a 'na•ve' view on this relation, which states that our experience inherits the temporal structure of events as they occur within the experience itself. Due to an extremely lucid writing style in this section of the book, the philosophy and history of the investigation of subjective time is accessible to any interested reader irrespective of his or her background.
From a philosophical and historical account of subjective time, this book then gracefully makes a transition to experimental approaches. The next section raises questions about the classical view that consciousness is a continuous stream of thought and is dedicated to the idea that the world is represented in a pseudo-continuous/semi-discrete fashion in the human mind. Authors provide a series of recent EEG and behavioral experimental evidence to make a claim that human brain functions are based on discrete sampling much like an analog movie reel, thus refuting James' view of continuous cognition. The book provides plenty of real world examples for general readers to relate, and to bridge the gap in classical and modern views on the topic.
Upon further reading, it becomes clear that the editors and writers of the book are gradually setting a stage for the readers in order to transport them to a deeper scientific and mathematical account of the topic of subjective time. Neuroscientist Konstantinos Moutoussis provides examples of experiments investigating time delay in the perception of color and motion in the visual system of the brain while theoretical philosopher Bruno Molder studies models of the neural basis of time as proposed by cognitive scientists Daniel Dennett and Rick Grush. These models essentially focus on emphasizing that perception of time in the brain is a product of the brain's interpretational processes and not a reflection of neural events making up those processes. From this point of view, what makes us 'us', is a 'coexistence' of these different neural events (such as hearing and vision) which are separated in both time and space.
Section V of the book revisits the question of the existence and quality of temporal windows or 'subjective presents'. It reviews experimental studies that describe the previously discussed, short ~30ms window of the specious present for elementary neural events as well as those which talk about a window length of the order of seconds for a successful integration of these primordial events. These windows form the bridge between objective and subjective time and are prone to manipulation. Cognitive philosopher and magician Thomas Fraps describes (in 'Time and Magic Ð Manipulating Subjective Temporality') manipulation of subjective time and attention in order to perform magical acts by using the tiny window of the 'subjective present'. Finally John Wearden et al. review experimental evidence to describe the manipulation of this temporal window and the associated real life experience of 'time flying' or 'dragging'.
In the final sections, the book takes a final leap in order to deal with neural mechanisms of temporality. Neuroscientist Dean V. Buonomano presents a variety of neural models, which have been proposed in order to understand how the brain may perform time discrimination. Neuroanatomist Ryota Kanai follows this with his proposal of a conceptual framework of illusory distortion of time and presents possible mechanisms by which time could be distorted in the brain. Intuitively, the simplest model of simultaneity perceives subjective simultaneity of two events as a race between reaction times or a judgment of temporal order. Chapters 19, 20 and 21 present evidence of the breaking down of these models and describe other factors such as music and gestures, which might contribute to the simultaneity and order judgments. Other factors explored, that might affect time perception, include emotion (for instance fear and anger speed up the subjective time perception). This section of the book presents a very focused and concrete set of literature review, which not only would be of interest to academics but also targets the general reader.
Ancient Greek philosophers saw time in light of movement or action. Behavioral and neuroimaging scientists Kielan Yarrow and Sukhvinder S. Obhi build on this idea and review time perception in the context of action. They describe chronostasis, a phenomenon where one experiences a momentary stopping down of a watch when glancing down (making an eye saccade) at the second hand of the watch. The extent to which our bodies, cognition and time perception is intertwined is detailed by psychologist Marc Wittmann in his chapter 'Embodied Time'. He proposes that the awareness of self is the awareness of passing time. Section X provides the reader with a comprehensive review of conditions that could significantly alter the perception of time. These include (i) pathological distortions, such as schizophrenia and depression, (ii) artificially induced distortions, such as hypnosis and LSD, (iii) natural alterations such as circadian fluctuations, menstrual cycle, physical properties of environment, spatial effects, emotions etc., and finally (iv) developmental disorders such as autism spectrum disorder, dyslexia and attention deficit hyperactivity disorder.
Finally, the editors Arstila and Lloyd conclude this extensive historical and scientific literature review of subjective time with a few suggestions, among which the proposition that subjective time consists of a complex structure that is embodied as well as embedded in the world. It, therefore, requires deeper investigation specifically in the light of basic neural mechanisms. In addition, a current understanding of the philosophical and neuroscientific literature on temporality is extremely important. Subjective Time: The Philosophy, Psychology and Neuroscience of Temporality attempts to bring knowledge from a wide variety of fields in order to present a simple, yet comprehensive review on the study of time. The organization of this book is structured and the writing style is moderately accessible. This allows interested readers with a scientific or non-scientific background to choose to focus on a specific topic of interest or gather a general understanding of subjective time. After all, in the words of Martin Luther King, Jr Ð "We must use time creatively".