"Psychology has a long past, but only a short history."Hermann Ebbinghaus, Abriss der Psychologie (Summary of Psychology), 1908
"The goal of research in evolutionary psychology is to discover and understand the design of the human mind."Leda Cosmides & John Tooby, Evolutionary Psychology: A Primer , 1997
Human beings are part animal, and like most animals we have at birth a large number of abilities. These abilities do not relate to learning or experience since at that stage we have none. They do relate to genetics and the development of our body and brain, based upon self-organizational processes. What these are and what abilities and biases they give us at birth is the subject of Evolutionary Psychology, which we introduce here. This field is not directly a complexity specialism but has much in common with the general themes studied in complexity.
Unlike many animals, human babies are born premature and do not complete their natal development for perhaps a year after birth, so it is not so apparent that babies do already have many abilities as a result of their genetic past. We have only however to look at the genetic similarity between humans and other species (over 98% DNA common with the apes) to realise that whatever abilities such animals have at birth we potentially have also. This means that we do not start life as a 'tabula rasa' or blank slate as so many assume, but already programmed with a set of hidden assumptions about the world and predispositions to process data and to act in certain instinctive ways.
On top of our genetic behavioural inheritance we add, as we grow up, two further layers. The first hones the learning ability of our brain that enables us to operate as a social being. This requires the co-ordination of muscles (walking, attention, speaking), the development of perception (discrimination, categories) and social awareness (other people as individuals). These abilities are those that we assume are produced by the neural network in our brain, which according to the neurological evidence organizes itself soon after birth, in accordance with the stimuli received from the senses. All these abilities are 'culture free', they are common to children the world over. The third layer is the culturally relative one, and adds (a little later) the particular language, cultural behaviours and the contextually sensitive knowledge that we need to be members of a particular society.
These added layers however do not replace our instincts, they merge with and augment them, like tools enabling their expression. Many of our natural behaviours have their roots in the inner or instinctive level of our being, and we can recognise these if we compare human behaviours to those of our near neighbours in the animal world to identify the similarities. This is not to say that we are 'determined' by our genes, that would be over simplistic (EP is not the same as sociobiology), simply that they bias our decisions in ways of which we are often not aware. Understanding these biases is an important step to understanding the workings of our self-organizing brain, and this relates this field to the complexity sciences.
Modern culture is a fairly recent thing, and there has not been enough time for our genes to alter to reflect our modern living conditions - that would take many thousands of generations (using data from genetic algorithm work). Thus our genetic makeup is still that appropriate to our primitive (mostly animal) environment. Studying biological evolution and the way animals solve problems is likely therefore to shed light on how we may do it, given the absence of cultural education. Indeed it seems fair to say that in the areas where we fail to educate any differently, then our behaviours will still be those of ancestral humans. It may even be the case that, despite education, our instincts still largely determine how we act.
Understanding the process that designed the human mind, the evolutionary biology of brain, will help us to separate out those behaviours specialised for animal tasks (mating, foraging, fighting and so on) from those more cultural or human. Studies in the fields of anthropology and ethology will also help here. It is assumed that specialised parts of the brain can develop in self-organizing ways from the genetic signals produced by our DNA, this mimics studies in the emergent creation of attractors from genomic networks (which is the complexity science addition to natural selection and developmental biology).
Despite much study in psychology, we still do not have an adequate understanding of the interplay of the unconscious on our behaviour, and how this relates to emotional states. Once we know how states such as prejudice, hate and anger evolved, then we will be in a much better position to understand how these supposedly 'irrational' aspects of mind relate to our more conscious intellectual and analytical abilities. Given this, we can then perhaps begin to overcome our primitive biases and better utilise our natural abilities for constructive rather than destructive ends. This is a major potential benefit of the evolutionary psychology approach.
Most of our emotional behaviours are not obviously conscious, we smile or scowl without thinking about it for instance. The irrational emotions of 'falling in love' are too well known to repeat, and our fears and outrages likewise often arise without intellectual control. These are all natural abilities of our minds, pre-programmed to respond in what were appropriate ways by influencing our behaviour in our previous environmental context. They may still be appropriate or they may not, but without scientific study of these (psychologically neglected) instinctive areas we can say nothing useful.
An evolutionary approach provides a powerful technique with which to analyse these areas. We have brain areas (of some sort) for navigating around the terrain, for mating, for social learning, for language, for feeding and many other unconscious skills. We also have a standard collection of reasoning and regulatory modules, integrating our systems and processing our sensory data (the visual processing areas are particularly well studied).
These functional specialisms have been well mapped nowadays in brain scans and clinical psychology, both in humans and animals, so we should have no doubt that they exist (at least in principle). How they arise is still an empirical question, but we can perhaps say that where our human abilities are common to those of animals that the cause was not cultural, at least in any linguistic human form. An evolutionary mechanism seems the most likely alternative.
The first principle relates to the brain as a circuit, an organised set of connections and units - the connectionist view, and brains are needed for environmental movement (plants don't have them). Second principle relates to appropriate specialisms, what we needed to detect, respond and adapt to. Third is proved by AI, image processing in human style is well beyond current supercomputers. Fourth relates to division of labour, our human societies have found it more efficient than generalisation, as have brains (e.g. vision). Fifth echoes the evolutionary time needed to evolve change that we mentioned earlier (99% of human existence was as hunter-gatherers, so genes still reflect that).
If we are to understand what our brains can do, we need to search for what the various functions are adapted to achieve. Taking an example, a sweet tooth enables us to distinguish nutritious ripe fruit from indigestible sour unripe fruit. This ancient ability was clearly adaptive to apes, but can be seen no longer to be so - we have other sources of non-sweet nutritious food. Relating all such abilities to our older evolutionary context in this sense, can identify many inbuilt biases, mostly common to close animal relatives (who still inhabit those environments).
Evolutionary psychology tries to identify the universal functional designs inherent in our brains at all levels (in other words the genetic commonality and not difference). This mirrors a concern in complexity science in which we wish to determine to what extent is structure self-organized and how much was imposed from outside - in that case we conclude that all structure is predominantly self-organizing, not imposed from outside (which just selects which options are contextually appropriate).
To learn anything we must have a mechanism, that applies whether we are talking of cells, brains, artificial neural networks or computers. We need a basic 'operating system' or ability to modify what is already there to make any useful (as opposed to random) change. We are not sculpted from outside but from inside (teachers do not physically change our brains), and this ability to learn itself requires an evolutionary explanation.
Genetic mechanisms cannot optimise the brain, there is insufficient data available in genes for that, so we cannot assume that we have a general purpose computer up there - unless we find a way of configuring brain 'software' on the fly for specialist lifetime tasks. Much more likely is that we have inherited working specialist emergent modules from our animal and human ancestors and that these are combined in an ad-hoc way (by random neural connection) - those that work are retained. This complexity hypothesis, close to the EP viewpoint, uses analogy between past situations and current ones to suggest appropriate strategies.
If we accept that our individual behaviour is partly genetically defined, then it is natural to extend these ideas to social areas. In complexity terms this says that biology, psychology and sociology are all 'systems' exhibiting the same structural features. Modern complex systems approaches to biology define the cell as an autopoietic system, in other words a system that produces and maintains itself. This idea of a self-sustaining system seems also appropriate to the individual mind and to society.
We can say therefore that as the cell evolves in order to adapt to and control its world (evolutionary biology), and the mind does the same at a higher level (evolutionary psychology), so we can assume that society does so too (evolutionary sociology). This latter field seems quite new, but relates to the influence of our psychological predispositions on the structure and processes of our society. It remains to be seen what will come of it.
A complexity view of mind would say that it operates at ' edge-of-chaos', a point where we would expect to find modularity and functions of different scales cooperating to maintain a coherent whole. This view is close to that of evolutionary psychology and the two can complement each other, as does complexity and evolutionary biology. Complexity science gives a systems overview on what we would expect to find in the mind as a complex system, and we can look to EP to experimentally verify predictions at the higher emergent levels, as does neurophysiology at the lower neuronal connectivity levels.
The Evolutionary Psychology emphasis on history and on adaptability is the welcome addition of dynamics to what has often seemed a static field, divorced from the biology on which it is undoubtably based. This reflects a similar move in Artificial Intelligence towards an environmentally situated mode of working, where actions take place in a context without conscious thought or abstract symbolism. All these ideas fit in with a view of complex systems as embodied coevolutionary partners in a multifaceted environment.