Evolution cannot be conscious, just as it cannot be unconscious, silly, clever, or anxious. However, conscious, sentient animals, including reflectively thinking humans, are one of the most amazing products of evolution. So while the question “Can Evolution be Conscious?” has no meaning, it is meaningful to ask how consciousness–the ability to have subjective experiences, such as smelling a rose or feeling fear–has evolved, and how, once in place, it has modified the rates and patterns of evolution. This is a particularly pertinent question when the effects of human reflective consciousness are considered. However, the effects of consciousness on evolutionary processes are more general.
How consciousness evolved and how consciousness has come to affect evolutionary processes are related issues. This is because biological consciousness–the only form of consciousness of which we are aware–is entailed by a particular, fairly sophisticated form of animal cognition, an open-ended ability to learn by association or, as we call it, “unlimited associative learning” (UAL). Animals with UAL can assign value to novel, composite stimuli and action-sequences, remember them, and use what has been learned for subsequent (future), second-order, learning. In our work we argue that UAL is the evolutionary marker of minimal consciousness (of subjective experiencing) because if we reverse-engineer from this learning ability to the underlying system enabling it, this enabling system has all the properties and capacities that characterize consciousness. These include: the unification of stimuli and actions and their accessibility to cognitive reference; formation of representations of the body, the world and the relations between them (leading to the construction of a virtual “self”); goal-directed behaviors, driven by motivations and emotions, based on a flexible value system that can assign valence to any unified percept and action-sequence; developmental flexibility that is based on processes of selection, including selective attention; and the formation of a durable (“thick”) present, which contains shadows of the past and is oriented towards the future.1,2
The evolutionary entanglement of consciousness and cognition means that animal behavior was driven not only by the direct functional significance of their behavior, but by the mediated values of desires and aversions, which were assigned to ontogenetically-constructed composite percepts and actions. An animal that could learn in such an open-ended manner could in theory assign value to an unlimited number of percepts and action patterns, and anticipate positive and negative effects on the basis of neutral cues associated with them. Such associative learning was a game-changing adaptation: animals could adapt ontogenetically rather than only phylogenetically. We have argued that this learning capacity drove the Cambrian explosion. Learned behaviors became fundamental to the fight and flight responses of mobile animals who lived in an ever-changing world, and to the construction of the niches that these animals and their offspring inhabited. For example, if an animal learned to exploit a novel and rich food source and consequently tended to stay and reproduce in areas where this resource was abundant, its offspring would have the same learning-environment and learning opportunities and would seek a similar niche; this would lead to habitat-specific habits, such as new styles of parental care, food handling, and fight-flight behaviors. Any behavioral, physiological or morphological feature that improved the ontogenetic adjustment to a specific learning environment would be selected, and would affect the evolution of interacting species. Rapid learning-guided evolution and learning-guided arms races have led to morphological and physiological diversification.3
Since what conscious animals regard as good or bad is context-dependent and not always optimal, new types of features can evolve. Consider an animal that discovers that a rare though recurrent fermenting food source gives it a very pleasurable feeling (even though the food makes it slightly less vigilant), and the habit of consuming this somewhat addictive food and even searching for it in the right season spreads throughout the group. The tradition may persist because of its strong memorable and pleasurable effects, and lead to the evolution of detoxifying enzymes, or to the consumption of foods with detoxifying microbiota, so that the slightly deleterious effects of the tradition are ameliorated. The evolution of the change in the digestive system or in the consumption of other foods was, in this case, driven by the pleasure the food gave to its consumers, rather than its nutritional value. Or consider a female selecting a mate because he has complex patterns of color on his wings and tail. The ability to perceive and enjoy these features leads to positive selection of males even if such males pay a survival cost for their attractiveness (a Fisherian sexual-selection scenario). It is not surprising that Darwin regarded animals that display complex mate-choice as a sign that they had highly evolved mentality.4 The evolution of consciousness did, of course, evolve much further: in some animals (birds such as corvids and parrots, mammals such as primates and elephants, and possibly some hymenopterans and cephalopods) imagination began to drive behavior.
The reflective consciousness of humans takes this mediated evolutionary effect of consciousness to a new level. Humans have symbolic systems of representation and communication, and through symbolic language they can communicate about the products of their imagination.5 Human evolution has led to complex artefacts, to the domestication of plants and animals, to elaborate social systems, to human moral laws, to exclusionary and cruel ideologies, to wars and horrific human and animal suffering, and to looming catastrophic ecological destruction led by short-sighted future interests. However, our reflective consciousness enables us to consider all these. We are a strange species, the evolution of which can be driven by visions of a better future-world and by abstract values like justice, beauty and truth. There is, therefore, some hope.
References:
- Ginsburg, S. and Jablonka, E. (in press) The Evolution of Sensitive Soul: Learning and the Origins of Consciousness. Cambridge, MA: The MIT Press.
- Bronfman, Z. Ginsburg, S. and Jablonka, E. (2016). The transition to minimal consciousness through the evolution of associative learning. Frontiers in Psychology 7, 1954.
- Ginsburg, S. and Jablonka, E. (2010). The evolution of associative learning: A factor in the Cambrian explosion. Journal of Theoretical Biology 266, 11–20.
- Darwin, C. (1871). The Descent of Man, and Selection in Relation to Sex. 1st edition. London: John Murray.
- Dor, D. (2015). The Instruction of Imagination: Language as a Social Communication Technology. Oxford: Oxford University Press.
