Neural activity within what has been termed the fronto-parietal control network was abnormal in patients with impaired self-awareness. The dorsal anterior cingulate cortex is a key part of this network that is involved in performance-monitoring. This region showed reduced functional connectivity to the rest of the fronto-parietal control network at 'rest'.
In addition, the anterior insulae, which are normally tightly linked to the dorsal anterior cingulate cortex, showed increased activity following errors in the impaired group. Interestingly, the traumatic brain injury patient group with normal performance-monitoring showed abnormally high activation of the right middle frontal gyrus, putamen and caudate in response to errors. So, what do we know about the evolution of this prized trait? Many psychologists and anthropologists hold that there is a hierarchy of consciousness that corresponds with increasing brain complexity.
At its base is the minimal consciousness attributed to animals with simple nervous systems. These minds are thought to be permanently adrift in a sea of raw sensory experiences, tossed around between perceptions such as colour, hunger, warmth and fear, with little awareness of their meaning.
Few minds are sophisticated enough to experience the world differently — through an introspective lens. Even then, they may have a limited sense of self. Smart animals like chimps and dolphins can recognise themselves in a mirror, but have they led us up the garden path?
What is the evidence for this hierarchy? After all, mental complexity is a slippery concept and, besides, none of us has insight into even the mind of another human, let alone a bat or a beetle. This disparity is mainly the result of the differing evolutionary demands that animals must meet to survive. For example, the nervous system of a sedentary, filter-feeding oyster consists of just two cell clusters.
These allow it to do exactly what an oyster needs to do — control its digestion, and transmit signals from light-sensing tentacles to the muscle that snaps it shut when a predator looms. Meanwhile, at the other end of the spectrum, there is one particular demand that seems to have led to the evolution of complex brains and could also have created the conditions for a sense of self to arise.
That challenge is dealing with the minds of others — be they prey, competitors or other members of your social group. To achieve this, brains needed to evolve from being simply things that experience sensations and thoughts to becoming their observer.
To do this, they needed to build a model of a mind, according to neuroscientist Michael Graziano at Princeton University. A model — be it for mind reading, weather forecasting or whatever — usually starts with some assumptions about the factors that contribute to the system in question and their relative importance. It then runs a simulation and, depending on how much the result diverges from physical observations, modifies the assumptions.
The model thus acquires an accurate representation of the forces at work, allowing it to make reasonable predictions about the future. If he is correct, then what you consciously experience is the simulation.
By extension, self-awareness is the conscious state of running that simulation on your own mind. Graziano believes we have no reason to put it on a pedestal. Moreover, it is hard to establish whether this ability is associated with uniquely complex biological machinery. After all, we are still struggling to pin down what consciousness looks like in the brain. Most researchers agree that the brain operates at least partly by generating simulations.
However, many disagree that consciousness is a functional piece of the modelling machinery. Instead, a widely held view sees it as the unintended by-product of information rushing through the closed loop of connections that is the brain.
Such emergent phenomena are common in nature. They give the mesmerising impression of complexity and intentionality, despite stemming from a system whose components operate with no regard for the phenomenon itself. One notable example is the collective behaviour of flocks of birds, which can be modelled using individuals driven by just two opposing forces — an instinct to follow their nearest few neighbours, and to back off if they get too close.
Apparent complexity emerges even in Petri-dish-bound bacterial colonies, where individual bacteria automatically respond to chemical signals secreted by their neighbours to regulate their proximity. Forgot password? Don't have an account? Sign in via your Institution. You could not be signed in, please check and try again.
Sign in with your library card Please enter your library card number. Search within Go to page:. Abstract and Keywords This chapter shows how the key to understanding self-awareness over the course of evolution and human development relies in the understanding of how the self resides in the complexities of the brain.
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