Smith earned a doctorate in neurosciences from Stanford University. He has conducted research in molecular biology, pharmacology, cancer, and neuroscience. Consciousness can be conceived to exist from the lowest invertebrate and vertebrate forms, up through human consciousness and far beyond.
- Account Options.
- Ghost Story;
- The Dimensions of Experience: A Natural History of Consciousness - Andrew P. Smith - Google Книги;
- Cry of the Wolf Singer (Wolf Singer Saga Book 1).
- Henry Cooper - The Authorised Biography;
Evidence that higher vertebrates express emotional feelings through functional emotional behavior serves to demonstrate the experience of consciousness. Group selection evidenced in metabolic and neuronal networks, as well as human societies, enable individual members to survive and develop.
Selection is determined by properties of the group rather than the qualities of individuals.
Review of The Dimensions of Experience () — Foreword Reviews
Each entity seeks a group that best suits its needs. These networks are highly resistant to disruption, and selective removal of one individual has little effect on the others. The author writes in a lucid style that makes the book accessible to nonscientists, and his wry humor brings alive the scientific detail he describes. Based on those aspects of their function and behavior that we can actually observe and measure, what can we say about what this consciousness is like?
The resulting story is one in which consciousness becomes increasingly more complex over evolutionary history, yet is based on facts of animal behavior that any reader, regardless of personal views on consciousness, can accept. In order to simply a vast amount of scientific literature, the book focuses on two general properties of consciousness and its behavioral manifestations: For example, the simplest invertebrate organisms experience one dimension of space, in the form of intensity discriminations made of simple stimuli such as light, touch and chemical substances.
Closely correlated with this one-dimensional experience of the outer world is the ability to make simple self-other discriminations, in which the organism in effect distinguishes itself one-dimensionally from the outer world. Somewhat more evolved invertebrates, such as arthropods, experience two dimensions of space, their perception being largely limited to shapes, contrasts, and surfaces. They can also distinguish between two dimensions in their relationships with other organisms, as exhibited in the ability to discriminate such classes of other as male vs.
The cluster analysis performed by Studerus et al. In light of the fact that behavioural investigations have explored the sense of unity for time and self independently, we too will begin by considering these two dimensions of unity independently before considering the eroding of boundaries more generally. One key feature of the psychedelic state is a distorted experience of time, with subjects typically reporting that time has stopped or slowed Ludwig Using objective measures of time perception based on interval matching or reproduction, a number of studies have shown significant impairments in both humans Wittmann et al.
Another consistent finding is that psychedelics alter the experience of the self Nour et al. In the analysis by Studerus et al. Although objective measures of self-perception are yet to be used in lab-based experiments, two recent studies have replicated earlier reports of the experience of ego-dissolution after administration of psilocybin Lebedev et al. In contrast to the relatively strong impact of psychedelics on the experience of unity and dissolution of self-boundaries, Studerus et al. A schematic summary of the key aspects of consciousness discussed in this paper, which illustrates the inappropriateness of a unidimensional account of consciousness.
The fact that the items relating to self and time cluster together suggests that the underlying feature being captured here is a generalized weakening or dissolution of the natural boundaries and segmentation that structure perceptual experience. At a much more basic perceptual level, Carter et al. The prevalence of synaesthesia in the psychedelic state could also be regarded as an example of inappropriate binding. Whether these alterations in the experience of unity involve improvements or impairments in conscious processing partially turns on contested issues concerning the nature of reality.
Consider, for example, the question of how the phenomenon of ego-dissolution should be understood. However, even if the self is ultimately a fiction e. Dennett ; Albahari ; Metzinger ; Bayne ; Letheby and Gerrans , a well-functioning organism must be able to distinguish changes in its environment that are due to its own activity from changes that are due to the activity of other agents. Thus, it seems likely that a blurring of the boundaries between future and past or oneself and others will compromise cognitive and behavioural function.
We turn now from surveying the general impact of psychedelics on consciousness to the question of what lessons these data have for accounts of consciousness. In our view, the lessons to be drawn are both negative and positive. Negatively, it is clear that the analysis of the psychedelic state puts further pressure on the idea that conscious states can be understood in terms of levels of consciousness. As we noted earlier, a central implication of the levels-based account is that distinct conscious states S1 and S2 , can be given a total ordering, such that either S1 is higher than S1 or vice-versa.
However, it is clear from the previous sections that the psychedelic state is neither higher nor lower than the state of ordinary waking awareness. This is important for a number of reasons. Firstly, it raises questions about the recent suggestion that psychedelics might be useful in treating patients with disorders of consciousness DoC such as the vegetative state and the minimally conscious state Carhart-Harris However, the considerations provided in this article undermine that assumption.
This point, together with the fact that psychedelics impair certain aspects of cognition and have the potential to disrupt the perception of space, time and the self, raises serious questions about their therapeutic value in the context of treating DoC patients. Second, the rejection of the levels-based account suggests that some of the most influential theories of consciousness need to be significantly revised. Although advocates of the GWT have said little about precisely how their account captures changes in conscious state, presentations of the theory typically assume a rather simplistic conception of conscious states.
Consider, for example, the way in which psychedelics alter attention, decision-making and working memory. In order to be a viable theory of consciousness, GWT will need to be developed so as to accommodate the multidimensional nature of consciousness. The data that we have reviewed also pose a challenge to the Integrated Information Theory IIT of consciousness, an influential complexity-based theory of consciousness. The considerations advanced in this paper raise questions about the plausibility of this view, for we have seen that global states cannot be ordered along a single dimension.
Of course, there are algorithms that can transform highly non-linear dynamic states into values that can be ordered along a single dimension. However, this is conceptually problematic, for it is far from clear that it is coherent to describe one individual as more or less conscious than another. The psychedelic state involves a conscious state that certainly differs from the conscious state associated with ordinary waking awareness, but there is no reason to think that individuals in the psychedelic state are more conscious or, for that matter, less conscious than individuals who are not in it.
If it is to be a viable theory of consciousness, IIT too will need to be developed so as to accommodate the multidimensional nature of consciousness.
The Dimensions of Experience
Positively, the analysis of the psychedelic state provides an important source of data for attempts to develop a multidimensional account of conscious states. By identifying the patterns of association and dissociation that characterize the psychedelic state we can determine the state space in terms of which conscious states are structured. Why do psychedelics increase the vividness, complexity and possibly also the bandwidth of sensory experience?
What explains the systematic effects that psychedelics have on the experience of unity across a wide range of domains e. Addressing these questions will help us to identify the various dimensions that structure consciousness. This task should be pursued in tandem with the investigation of other conscious states, such as those that are associated with sleep, sedation, and the post-comatose disorders of consciousness e. For example, we might ask whether attention qualifies as a separate dimension within this state-space, or whether changes in conscious state are better modelled by distinguishing between different aspects of attention for example, sustained attention versus selective attention.
The study of psychedelics also provides an important—and neglected—source of data for understanding the neural basis of consciousness. We know a lot about the neurobiology of psychedelics for a detailed review see Nichols For example, we know that psychedelics act predominantly through 5-HT2A receptor activation, and we know where these receptors are typically located in the brain.
Further, through the use of animal models Aghajanian and Marek ; Halberstadt and Geyer and human neuroimaging studies Dos Santos et al. These techniques provide us with a powerful and under-utilized avenue for understanding the neural basis of consciousness.
Introduction
Although we have identified some of the more prominent changes in consciousness associated with psychedelic states, we acknowledge the limitations associated with the data we have used. The ASC represents one of the best available self-report measures of psychedelic effects and has impressive reliability and drug selectivity, but it should not be regarded as a comprehensive survey of the impact of psychedelics on consciousness.
Thus, although the data surveyed here are incompatible with a unidimensional account of consciousness, they are too limited to allow for a formal assessment of the number of dimensions that would best characterise consciousness. As we gain a better understanding of the ways in which the subjective and functional dimensions of consciousness can change, so too we will gain a better understanding of the dimensional nature of consciousness, and thus better grasp what it would be like to be in each of the various states of consciousness.
Oxford University Press is a department of the University of Oxford.
Product details
It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide. Sign In or Create an Account. Close mobile search navigation Article navigation. Charting the Psychedelic State of Consciousness. Implication for Consciousness Science. Dimensions of consciousness and the psychedelic state Tim Bayne.
- Pasiones Salvajes (Doncellas cautivas II) (Spanish Edition);
- Special offers and product promotions;
- Separate Truth (Annies Story Book 1)!
Neuroscience of Consciousness , Volume , Issue 1, 1 January , niy, https: Abstract It has often been suggested in the popular and academic literature that the psychedelic state qualifies as a higher state of consciousness relative to the state of normal waking awareness. View large Download slide. Consciousness in humans and non-human animals: Human studies of prepulse inhibition of startle: From unresponsive wakefulness to minimally conscious PLUS and functional locked-in syndromes: