Consciousness is defined as an inner feeling of selfhood and awareness of external objects. The issue of consciousness is widely discussed and researched. The more humans know about the space and the world around, the more they want to know about themselves. Consciousness as a scientific notion is investigated by philosophers, psychologists, physiatrists, biologists etc.
Last time people start thinking of the fact that they are not the only living creatures, which possess consciousness. Mammals, birds, insects demonstrate behavior that can be evaluated as appearance of consciousness. Rene Descartes thought that animals have no soul therefore they cannot posses any feelings, including the awareness of themselves and other objects. During medieval time this issues were only the discussion questions for philosophers. But the times have changed. Nowadays, medical equipment allows tracing consciousness and converting it into impulses. And animals, that always were objects of biological researches before people did experiments on themselves, appeared to be more important than it was thought before.
Griffin (2000) writes that scientists are now sure that animals posses consciousness. Not all animals and not all the time but some of them and in some cases. Researchers are more interested to discover the content of animal consciousness. In his article he investigated the history of such researches and points out on the careful attention on the human consciousness in 1990s with the technical progress and this led to more thorough investigation of the consciousness in other species. Thus grey parrots and monkeys were examined. The experiments conducted by the scientists proved that animals can posses some primary consciousness.
The standard behavioral mark for human consciousness is the ability to report events, feelings and emotions with accuracy (Seth, Baars & Edelman, 2005, p. 119). The method of accurate report is widely used for scientific and medical researches on humans but can hardly be used on other species. It is almost impossible to get first person report because animals cannot express their experience in a matter people can fully understand (Edelman, Baars & Seth, 2004, p. 170). The accurate report does not limited to verbal responses. Any voluntary reaction can be considered as a response. Yet, the accurate cannot be applied to all species. It is used for primates as they posses language of gestures and can express their emotions. It is even harder wit non-mammalian species. Therefore scientists developed a range of criteria to observe marks of consciousness among animals.
One approach to the issues of consciousness is to set evidences of human consciousness as a benchmark. It limits experiments to some paradigms. For example, binocular rivalry has been one of the major experimental techniques for exploring consciousness in recent years (Baars, 2005, p.11). This approach is quite reliable because mammals and even birds have the same or close brain structure and therefore the same processes can take place. Another approach distinguishes two kinds of consciousness: primary one, when different percepts are united into episodic scenes, and higher-order consciousness, which includes self awareness (Edelman, 1989).
One of the easiest criteria to be traced is the EEG signature. It is the electrical activity of the brain ranging from 12 to 70 Hz. It differs from the activity in unconscious states. REM dreaming can be observed among early mammals (Baars, 2005, p. 10). It was also proved that REM functions are to stimulate and prepare mammals to different situations, including threatening. This means that such mammals as cats and dogs can be considered conscious.
Another criterion of consciousness developed by scientists is activity of cortex and thalamus. Investigations of bird and octopuses (Edelman, Seth, 2009, p.479), (Edelman, Baars & Seth, 2004, p. 172, p. 177) showed that both species posses cortex and thalamus complex or structures with the same functions. Basically, this means that not only mammals but also non-mammalian species have primary consciousness.
Furthermore, another interesting means to discover consciousness among non-humans is a sensory blinding. Baars (2005, p. 13) describes the notion of commentary key as evidence of mammalian consciousness. It is observed among monkeys and cats. It allows animals to give behavioral comments on previous response. Human patients with cortical blindness continue to make accurate discriminations despite the fact of being blind. Scientists were interested in macaques’ behavior in such situation. Monkeys’ brains resemble the functions of the human ones in a number of issues. The commentary key provides an equivalent to reportability criterion in humans.
Consciousness presents range of contents – different senses, images, concepts, interactions. According to Thomas Nagel (Seth, Baars & Edelman, 2005, p. 124) it is like to be a bat, it uses its sonar to determine the distance to the objects, their colors and other features. Basically, bat possesses unique physical type – its “batness”. And it makes it conscious, at least from the philosophic point of view.
Many scientists state that the most important evidence of consciousness among animals is ability of self-recognition. Prior, Schwarz and Guentuerkuen (2008) investigated this issue among birds, Suddendorf and Collier-Baker (2009) – on the example of lesser apes (gibbons), and Plotnik, de Waal and Reiss (2006) devoted their study to Asian elephants. The most productive way to conduct this test is to use a mirror and a mark on the body of an animal to observe whether the animal would react on the reflection. The mirror self-recognition (MSR) was previously applied humans and apes because it is correlated with higher order forms of consciousness. Recently, the studies proved that dolphins also react on mirrors in a way that suggest that their awareness of being reflected in the mirror.
Therefore, three groups of scientists chose other objects for their researches. The first group investigated the behavior of Magpies (Pica pica). Birds were put in cages with hanged mirrors and then marked. Pica pica demonstrated such kinds of self-recognition behavior – they tried to reach mark with the beak, touch the mark with the foot. It was mark-directed behavior. Besides, birds demonstrated not related to the mark behavior. This means that they recognize themselves and discover themselves using mirror. So, therefore, avians possess self-consciousness, which is the highest form consciousness. The second group made the same test with gibbons. These apes failed to recognize themselves but this provides an interesting insight into the chain of hominids because bigger apes and humans possess this ability. Elephants showed almost the same results as birds.
All in all, there are more facts in favor of the fact that animals are conscious than vice versa. This means that humans should be more attentive to other species because it is their chance to understand each other. It can be a way to harmony between all inhabitants of the Earth.
Baars, B. J. (2005). Subjective experience is probably not limited to humans: The evidence from neurobiology and behavior. Consciousness and Cognition, 14, 7-21.
Edelman, D. B., Baars, B. J., Seth, A. K. (2004). Identifying hallmarks of consciousness in non-mammalian species. Consciousness and Cognition, 14, 169-187.
Edelman, D. B., Seth, A. K. (2009). Animal consciousness: a synthetic approach. Trends in Neurosciences, 9 (32), 476-484.
Edelman, G. M. (1989). The remembered present. New York: Basic Books.
Griffin, D. R. (2000). Scientific approaches to animal consciousness. American Zoologist, 4, 889-892.
Plotnik, J. M., de Waal, F. B. M, Reiss, D. (2006). Self-recognition in an Asian elephant. Proceedings of the National Academy of Sciences, 45 (103), 17053-17057.
Prior, H., Schwarz, A., Guenttuerkuen, O. (2008). Mirror-induced behavior in the Magpie (Pica pica): Evidence of recognition. PLoS Biology, 6 (8), 1642-1650.
Suddendorf, T., Collier-Baker, E. (2009). The evolution of primate visual self-recognition: evidence of absence in lesser apes. Proceedings of the Royal Society B, 276, 1671-1677.
Seth, A. K., Baars, B. J., Edelman, D. B. (2005). Criteria for consciousness in humans and other mammals. Consciousness and Cognition, 14, 119-139.