Many mammals are highly social animals with a variety of behavioral attributes that evolved to facilitate social interaction, but humans seem to be unique in their degree of sociability. Two related features of the human brain are particularly important to human sociality and to gene-culture coevolution: brain plasticity and the existence of Von Economo neurons.
Neurons are a type of cell that processes information and transmits it to and from the brain by electrical and chemical signaling. A remarkable finding from neuroscience is that most of the neurons in the human brain develop after birth and the way they are configured depends critically on how a child is socialized. It is another way that variability can be introduced into evolutionary mix. Wexler (2006, 3) writes about the evolutionary advantages of brain plasticity:
There is an evolutionary advantage for life forms that reproduce sexually because mixing of genetic material from parents produces variety in their offspring. Thus, different individuals have different characteristics, which increases the likelihood that some members of the group will be able to function and reproduce even when the environment in which the group lives changes. In an analogous manner, the distinctive postnatal shaping of each individual’s brain function through interaction with other people, and through his or her own mix of sensory inputs, creates an endless variety of individuals with different functional characteristics. This broadens the range of adaptive and problem-solving capabilities well beyond the variability achieved by sexual reproduction.
A related insight is also important for successful societal transitions. Humans alter the environment that shapes culture and brain development to an unprecedented degree.
These human alterations in the shared social environment include physical structures, laws and other codes of behavior, food and clothes, spoken and written language, and music and other arts…It is this ability to shape the environment that in turn shapes our brains that has allowed human adaptability and capability to develop at a much faster rate than is possible through alteration of the genetic code itself (Wexler 2006, 3).
Evolutionary biologists call the ability of species to shape their environments niche construction (Laland, Odling-Smee and Myles 2010). For example, animals build nests and construct burrows. Niche construction due to cultural processes can be much more potent and more rapid than non-cultural (gene-based) processes. Most of the world’s population (although certainly not all) live in a material environment almost entirely created by humans. Very little of our well-being comes directly from the natural world (although ultimately, of course, it all does). We have also adapted technologically, socially, and perhaps even neurologically in ways that shield us from the negative effects of our activities on the earth’s life support systems. This is called counteractive niche construction (Laland, Odling-Smee and Myles 2010). An example is bees using collected water to cool their hives. Humans have used technology and the built environment to live in habitats from the arctic to inhospitable deserts. The ability of humans to buffer themselves from environmental change makes it difficult to get public support to correct human-induced negative impacts like climate change and biodiversity loss. For most people rapid environmental change is something in the distant future affecting people in distant lands, not them. But the good news is that the same skills that gave humans an unrivaled ability to adapt to new situations and meet new challenges. The importance of post-natal brain development in humans means that we have the innate ability to change our attitudes and ways of living both to reduce our pressure on the environment and to adapt to the inevitable changes we have set in motion.
Another remarkable finding from neuroscience is the presence in the human brain of Von Economo or spindle neurons that apparently evolved to enable people to make rapid decisions in social context. Sherwood, Subiaul, and Zadwidski (2008, 433) write:
Based on the location, neurochemistry, and morphological characteristics of Von Economo neurons, it has been hypothesized that they transmit rapid outputs to subcortical regions (Allman et al. 2005). It is interesting that these specialized projection neuron types have been identified in cortical areas that are positioned at the interface between emotional and cognitive processing. Given their characteristics, it has been speculated that Von Economo neutrons are designed for quick signaling of an appropriate response in the context of social ambiguity (Allman et al. 2005). Enhancements of this ability would be particularly important in the context of fission-fusion communities, such as those of panids and possibly the LCA [last common ancestor], with complex networks of social interactions and potential uncertainties at reunions.
Allman et al. (2005, 370) argue that these neurons help humans to adjust quickly to rapidly changing social situations:
We hypothesize that the VENs and associated circuitry enable us to reduce complex social and cultural dimensions of decision-making into a single dimension that facilitates the rapid execution of decisions. Other animals are not encumbered by such elaborate social and cultural contingencies to their decision-making and thus do not require such a system for rapid intuitive choice.
Von Economo neurons are also found (in much smaller numbers) in great apes and whales and dolphins, other highly intelligent species with complex social systems. In humans, most of these neurons are formed after birth and develop according to environmental influences, again pointing to the blurred line between heredity and socialization. The latest neurological evidence suggests that human behavior is uniquely social and that critical neuro patterns of intimacy and trust must be established during infancy to condition the brain for social bonding and empathy, as well as learning and cultural transmission through childhood and adulthood. Although most neurons are formed within a few years after birth there is evidence that the human brain can and does modify itself throughout life in response to environmental conditioning. Understanding the social basis of human cognitive development is key to comprehending the nature of decision making (and the importance of reference groups, for example). And both are critical to formulating successful pro-social and environmental policies and to gaining public acceptance of these policies.
Neuroscience, because of its grounding in human biological and social evolution, has the potential to provide a solid, science-based framework to help understand the regularities of human behavior within highly evolved social systems. This may help to inform us about how the transition to sustainability might take shape as we struggle to make it through the climate disruptions, population pressures and resource bottlenecks of the 21st century. Neuroscience can help us understand the ultimate causes of human behavior (evolution through natural selection) as opposed to proximate causes (particular learned cultural practices).