Secondary consciousness is an individual's accessibility to their history and plans. The ability allows its possessors to go beyond the limits of the remembered present of primary consciousness.Edelman, G. M. (2003). Naturalizing consciousness: a theoretical framework. Proc. Natl. Acad. Sci. U.S.A. 100, 5520–5524. Primary consciousness can be defined as simple awareness that includes perception and emotion. As such, it is ascribed to most animals. By contrast, secondary consciousness depends on and includes such features as self-reflective awareness, abstract thinking, volition and metacognition.Edelman, G. M. (1992). Bright Air, Brilliant Fire: On the Matter of the Mind. Basic Books, New York. The term was coined by Gerald Edelman.
Brief history and overview
Since Descartes's proposal of dualism, it became a general consensus that the mind had become a matter of philosophy and that science was not able to penetrate the issue of consciousness- that consciousness was outside of space and time. However, over the last 20 years, many scholars have begun to move toward a science of consciousness. Such notable neuroscientists that have led the move to neural correlates of the self and of consciousness are Antonio Damasio and Gerald Edelman. Damasio has demonstrated that emotions and their biological foundation play a critical role in high level cognition,Damasio, A. (1999). The Feeling of What Happens: Body, Emotion and the Making ofConsciousness. Harcourt Brace, 1999.Damasio, A. (2003). Feelings of emotion and the self. In J. LeDoux, J. Debiec & H. Moss (Eds.), Self: from Soul to Brain (Vol. 1001, pp. 253–261). New York: New York Acad Sciences. and Edelman has created a framework for analyzing consciousness through a scientific outlook. The current problem consciousness researchers face involves explaining how and why consciousness arises from neural computation.Chalmers D J, Facing up to the problem of consciousness, J Cons Stud, 2 (1995) 200.Chalmers D J, The conscious mind: In search of a fundamental theory (Oxford University Press, New York) 1996. In his research on this problem, Edelman has developed a theory of consciousness, in which he has coined the terms primary consciousness and secondary consciousness. The author puts forward the belief that consciousness is a particular kind of brain process; linked and integrated, yet complex and differentiated.Edelman, G. M., Tononi, G. (2000). A Universe of Consciousness: How Matter Becomes Imagination. New York: Basic Books
Evolution towards secondary consciousness Edelman argues that the evolutionary emergence of consciousness depended on the natural selection of neural systems that gave rise to consciousness, but not on selection for consciousness itself. He is noted for his theory of neuronal group selection, also known as Neural Darwinism, which posits that consciousness is the product of natural selection. He believes consciousness is not something separate from the real world, thus the attempt to eliminate Descartes’ "dualism" as a possible consideration. He also rejects theories based on the notion that the brain is a computer or an instructional system. Instead, he suggests that the brain is a selectional system, one in which large numbers of variant circuits are generated epigenetically. He claims the potential connectivity in the neural net "far exceeds the number of elementary particles in the universe"Edelman, G. M. (2004). Wider than the sky: a revolutionary view of consciousness. Penguin Press Science, London, UK.
Dynamic core hypothesis and re-entry Dynamic core hypothesis
Edelman elaborates on the dynamic core hypothesis (DCH), which describes the thalamocortical region- the region believed to be the integration center of consciousness. The DCH reflects the use and disuse of interconnected neuronal networks during stimulation of this region. It has been shown through computer models that neuronal groups existing in the cerebral cortex and thalamus interact in the form of synchronous oscillation.Werner, A. G. (2007). Metastability, criticality and phase transitions in brain and its models. Biosystems, 90(2), 496–508 The interaction between distinct neuronal groups forms the "dynamic core" and may help explain the nature of conscious experience.
Re-entry
Edelman integrates the DCH hypothesis into Neural Darwinism, in which metastable interactions in the thalamocortical region cause a process of selectionism through re-entry, a host of internal feedback loops. "Re-entry", as Edelman states, "provides the critical means by which the activities of distributed multiple brain areas are linked, bound, and then dynamically altered in time during perceptual categorization. Both diversity and re-entry are necessary to account for the fundamental properties of conscious experience." These re-entrant signals are reinforced by areas Edelman calls "degenerate". Degeneracy doesn't imply deterioration, but instead redundancy as many areas in the brain handle the same or similar tasks. With this brain structure emerging in early humans, selection could favor certain brains and pass their patterns down the generations. Habits once erratic and highly individual ultimately became the social norm.
Exhibiting secondary consciousness in the animal kingdom While animals with primary consciousness have long-term memory, they lack explicit narrative, and, at best, can only deal with the immediate scene in the remembered present. While they still have an advantage over animals lacking such ability, evolution has brought forth a growing complexity in consciousness, particularly in mammals. Animals with this complexity are said to have secondary consciousness. Secondary consciousness is seen in animals with semantic capabilities, such as the four great apes. It is present in its richest form in the human species, which is unique in possessing complex language made up of syntax and semantics. In considering how the neural mechanisms underlying primary consciousness arose and were maintained during evolution, it is proposed that at some time around the divergence of reptiles into mammals and then into birds, the embryological development of large numbers of new reciprocal connections allowed rich re-entrant activity to take place between the more posterior brain systems carrying out perceptual categorization and the more frontally located systems responsible for value-category memory. The ability of an animal to relate a present complex scene to its own previous history of learning conferred an adaptive evolutionary advantage. At much later evolutionary epochs, further re-entrant circuits appeared that linked semantic and linguistic performance to categorical and conceptual memory systems. This development enabled the emergence of secondary consciousness.Edelman, G. M. (200). Second Nature:Brain Science and Human Knowledge. Yale University Press, New Haven, CT.
Self-recognition
For the advocates of the idea of a secondary consciousness, self-recognition serves as a critical component and a key defining measure. What is most interesting then, is the evolutionary appeal that arises with the concept of self-recognition. In non-human species and in children, the "mirror test" has been used as an indicator of self-awareness. In these experiments, subjects are placed in front of a mirror and provided with a mark that cannot be seen directly but is visible in the mirror.Bischof-Köhler, D. (1991). The development of empathy in infants. In M.E. Lamb & H. Keller (eds.), Infant Development. Perspectives from German speaking countries (245–273).Prior, H., Schwarz, A., & Gunturkun, O. (2008). Mirror-induced behavior in the magpie (Pica pica): Evidence of self-recognition. Plos Biology, 6(8), 1642–1650.
There have been numerous findings in the past 30 years which display fairly clear evidence of possessors of self-recognition including the following animals: Chimpanzees, orangutans and gorillas.Gallup GG Jr (1970) Chimpanzees: self-recognition. Science 167: 86–87.Walraven V, van Elsacker L, Verheyen R (1995) Reactions of a group of pygmy chimpanzees (Pan paniscus) to their mirror images: evidence of self-recognition. Primates 36: 145–150.Patterson FGP, Cohn RH (1994) Self-recognition and self-awareness in lowland gorillas. In: Parker ST, Mitchell RW, editors. Self-awareness in animals and humans: developmental perspectives. New York (New York): Cambridge University Press. pp. 273–290. Dolphins and elephants. Findings suggestive of self-recognition in mammals other than apes have been reported.Reiss D, Marino L (2001) Mirror self-recognition in the bottlenose dolphin: a case of cognitive convergence. Proc Natl Acad Sci U S A 98: 5937–5942.Plotnik JM, de Waal FBM, Reiss D (2006) Self-recognition in an Asian elephant. Proc Natl Acad Sci U S A 103: 17053–17057. Magpies. It should be mentioned that even in the chimpanzee, the species most studied and with the most convincing findings, clear-cut evidence of self-recognition is not obtained in all individuals tested. Occurrence is about 75% in young adults and considerably less in young and old individuals.Povinelli DJ, Rulf AB, Landau KR, Bierschwale DT (1993) Self-recognition in chimpanzees (Pan troglodytes): distribution, ontogeny, and patterns of emergence. J Comp Psychol 107: 347–372. For Monkeys, non-primate mammals, and in a number of bird species, exploration of the mirror and social displays were observed. However, hints at mirror-induced self-directed behavior have been obtained.Hyatt CW (1998) Responses of gibbons (Hylobates lar) to their mirror images. Am J Primatol 45: 307–311.
Self-recognition study in the magpie
It was recently thought that self-recognition was restricted to mammals with large brains and highly evolved social cognition but absent from animals without a neocortex. However, in a recent study, an investigation of self-recognition in corvids was carried out, and significant result quantified the ability of self-recognition in the magpie. Mammals and birds inherited the same brain components from their last common ancestor nearly 300 million years ago, and have since independently evolved and formed significantly different brain types. The results of the mirror and mark tests showed that neocortex-less magpies are capable of understanding that a mirror image belongs to their own body. The findings show that magpies respond in the mirror and mark test in a manner similar to apes, dolphins and elephants. This is a remarkable capability that, although not fully concrete in its determination of self-recognition, is at least a prerequisite of self-recognition. This is not only of interest regarding the convergent evolution of social intelligence; it is also valuable for an understanding of the general principles that govern cognitive evolution and their underlying neural mechanisms. The magpies were chosen to study based on their empathy/ lifestyle, a possible precursor for their ability of self-awareness.
Research on animal consciousness
Many researchers of consciousness have looked upon such types of research in animals as significant and interesting approaches. Ursula Voss of the Universität Bonn believes that the theory of protoconsciousness may serve as adequate explanation for self-recognition found in this bird species, as they would develop secondary consciousness during REM sleep. She added that many types of birds have very sophisticated language systems. Don Kuiken of the University of Alberta finds such research interesting as well as if we continue to study consciousness with animal models (with differing types of consciousness), we would be able to separate the different forms of reflectiveness found in today's world.
Lucid vs. non-lucid dreaming as a model