The Cambridge Declaration on Consciousness*

On this day of July 7, 2012,  a prominent international  group  of  cognitive  neuroscientists, neuropharmacologists, neurophysiologists, neuroanatomists and computational neuroscientists gathered at The University of  Cambridge  to  reassess the neurobiological substrates of  conscious experience and related behaviors in human and non-human animals. While comparative research on  this topic is naturally hampered by the inability of non-human animals, and often humans, to clearly and  readily communicate about their internal states, the following observations  can be stated unequivocally:


* The field of Consciousness research is rapidly evolving. Abundant new techniques and strategies for human and non-human animal research have been developed. Consequently, more data is becoming  readily  available,  and this calls for  a  periodic  reevaluation of previously held  reconceptions in this field. Studies of non-human animals have shown that homologous brain circuits correlated with conscious experience and perception can be selectively facilitated and disrupted to assess whether they are in fact necessary for those  experiences.  Moreover, in humans, new non-invasive techniques are  readily  available to survey  the correlates of consciousness.  


° The neural substrates of emotions do not appear to be confined to cortical structures. In fact, subcortical neural networks  aroused during  affective  states  in humans are  also  critically important for generating emotional behaviors in animals. Artificial arousal of the same brain regions generates corresponding behavior and feeling states in both humans and non-human animals.  Wherever  in the brain one evokes instinctual  emotional behaviors in  non-human animals, many of the ensuing behaviors are consistent with experienced feeling states, including those internal states that are rewarding and punishing. Deep brain stimulation of these systems in humans  can  also  generate  similar affective states.  Systems  associated with affect  are concentrated in subcortical regions where neural homologies abound. Young human and nonhuman  animals without neocortices retain these brain-mind functions.  Furthermore, neural circuits supporting  behavioral/electrophysiological states of  attentiveness, sleep and decision making appear to have arisen in evolution as early as the invertebrate radiation, being evident in insects and cephalopod mollusks (e.g., octopus).


° Birds appear to offer, in their behavior, neurophysiology, and neuroanatomy a striking case of parallel evolution of  consciousness.  Evidence of near human-like levels of consciousness has been  most dramatically  observed in  African grey  parrots. Mammalian and avian emotional networks and  cognitive  microcircuitries appear to be far more homologous than previously thought. Moreover, certain species of birds have been found to exhibit  neural sleep patterns similar to those of mammals, including REM sleep and, as was demonstrated in zebra finches, 
neurophysiological patterns, previously thought to require a mammalian neocortex. Magpies in particular have been shown to exhibit striking similarities to humans, great apes, dolphins, and elephants in studies of mirror self-recognition.


° In humans, the effect of certain hallucinogens appears to be associated with a disruption in cortical  feedforward and feedback  processing.  Pharmacological interventions in  non-human animals with compounds known to affect conscious behavior in humans can lead to similar perturbations in behavior in non-human animals. In humans, there is evidence to suggest that awareness is correlated with cortical activity, which does not exclude possible contributions by subcortical or early cortical processing, as in visual awareness. Evidence that human and nonhuman  animal emotional feelings arise from homologous subcortical brain networks  provide compelling evidence for evolutionarily shared primal affective qualia.


We declare the following: “The absence of a neocortex does not appear to preclude an organism from experiencing affective states. Convergent evidence indicates that  non-human  animals have the neuroanatomical,  neurochemical, and neurophysiological substrates of conscious states along with the capacity to exhibit intentional behaviors. Consequently, the weight of evidence  indicates that humans are not unique in possessing the neurological substrates that generate consciousness. Nonhuman animals, including all mammals and birds, and many other creatures, including octopuses, also possess these neurological substrates.”


* The Cambridge Declaration on Consciousness was written by Philip Low and edited by Jaak Panksepp, Diana Reiss, David Edelman, Bruno Van Swinderen, Philip Low and Christof Koch. The Declaration was publicly  proclaimed in  Cambridge, UK, on July 7, 2012, at the Francis Crick Memorial Conference on Consciousness in Human and non-Human Animals, at Churchill College, University of Cambridge, by Low, Edelman and Koch. The Declaration was signed by the conference participants that very evening, in the presence of Stephen Hawking, in the Balfour Room atthe Hotel du Vin in Cambridge, UK. The signing ceremony was memorialized by CBS 60 Minutes.