Why Consciousness Evolved from Brain Physiology

Why did consciousness emerge from the brain’s underlying physiology? Although it is a lively field within neuroscience, consciousness research remains marked by dispute and controversy, with several competing theories vying for acceptance.

A recent scoping review examining more than 1,000 papers found over 20 distinct theoretical explanations. Philosophers such as David Chalmers maintain that no individual scientific theory can fully account for consciousness.

We understand consciousness as embodied subjective awareness, encompassing self-awareness. In a recent paper in Interalia (which is not peer-reviewed), we suggest that the strong influence of intuition is one reason for this impasse.

Others have reached a similar conclusion. Social scientist Jacy Reese Anthis writes: "much of the debate on the fundamental nature of consciousness takes the form of intuition jousting, in which the different parties each report their own strong intuitions and joust them against each other."

The dangers of intuition

Crucial intuitive assumptions include the belief that mental processes are separate from physical bodies - mind-body dualism - and that mental processes generate and direct our choices and behaviour - mental causation. Such beliefs are reinforced by a lifetime of subjective experience.

They occur across every human culture. They also matter because they underpin most liberal democracies and criminal justice systems, while proving highly resistant to contradictory evidence.

This is because social and cultural ideas including free will, human rights, democracy, justice and moral responsibility strongly support them. Each of these concepts presupposes that consciousness has a central, controlling role.

Yet intuition is an automatic cognitive process that evolved to offer rapid, dependable explanations and predictions. It does this without requiring us to understand either how or why we possess that knowledge.

Its results consequently influence how we see and interpret the everyday world, without demanding prolonged reflection or formal analytical accounts.

Although intuitive beliefs are useful - and often essential - in everyday life, they may be mistaken. They can also obstruct scientific literacy.

Intuitive explanations of consciousness ultimately place us in control, as the "captain of our own ship". We assume that merely experiencing consciousness tells us what it is and what it does. Thoughts, intentions and desires are regarded as forces that determine and control what we do.

The broad, implicit acceptance of these intuitive accounts partly explains why the formal investigation of consciousness remained on the fringes of mainstream neuroscience until the late 20th century.

For scientific models of consciousness, the continuing challenge is to incorporate these intuitive accounts into a materialist framework that accords with neuroscience’s findings.

Although science currently has no explanation for how brain tissue produces or sustains subjective experience, most neuroscientists agree that subjective experience results from brain processes.

Consciousness and its social purpose

If this is so, why did consciousness, understood as subjective awareness, evolve?

Consciousness presumably developed alongside the nervous system. Several theories hold that its principal adaptive function - giving an organism advantages for survival and reproduction - is enabling voluntary movement.

We commonly connect volition with will, agency and individuality. It is therefore understandable to suppose that consciousness evolved for the benefit of individual people.

However, we have argued that consciousness may instead have developed to support vital social adaptive functions. Rather than aiding individuals’ survival, it may have evolved to allow us to communicate our experienced ideas and feelings to the broader world. This, in turn, could support the survival and wellbeing of the species as a whole.

This proposal aligns with emerging ideas in genetics. Evolutionary science has traditionally concentrated on individual genes, but there is increasing acknowledgement that natural selection in humans operates across several levels. Culture and society, for instance, affect which traits are transmitted between generations, as we value certain traits more than others.

At the centre of our account is sociality: the propensity of individuals and groups to form social connections and live in communities. We view it as a crucial survival strategy that shapes the evolution of the brain and cognition.

Using this social-evolutionary framework, we propose that subjective awareness has no separate ability to causally affect other psychological processes or actions, such as starting a particular course of action.

Other researchers have previously described the possibility that subjective awareness serves a social purpose.

Subjective awareness, agency and accountability

However, arguing that subjective awareness has no causal influence does not mean denying that subjective experience is real, nor claiming that such experience is an illusion.

Our model removes subjective awareness from the mind’s conventional driving seat, but it does not suggest that private internal experiences have no value. On the contrary, the value we attach to them is precisely why intuitive explanations remain persuasive and widespread within social and legal systems of organisation, as well as psychology.

Although it may seem counter-intuitive to assign agency and personal accountability to a biological collection of nerve cells, it is reasonable that deeply valued social concepts - including free will, truth, honesty and fairness - can meaningfully be assigned to people as accountable members of a social community.

Consider that, while our biological nature runs deep, our social nature is largely shaped by the roles we occupy and the interactions we have in society. The mind’s mental architecture should therefore be highly adapted to exchanging and receiving information, ideas and feelings.

Accordingly, even though brains, as biological organs, cannot themselves possess responsibility or agency, legal and social traditions have long treated individuals as accountable for their behaviour.

A more scientific explanation of subjective awareness depends on accepting that biology and culture jointly shape the way brains evolve. Subjective awareness is only one component of the brain’s far broader mental architecture, which is designed to promote species survival and wellbeing.

Peter W Halligan, Hon Professor of Neuropsychology, Cardiff University and David A Oakley, Emeritus Professor of Psychology, UCL

This article is republished from The Conversation under a Creative Commons licence. Read the original article.