Mirror Neurons and the ERR
The experimental evidence for mirror neurons is very strong. Functional magnetic resonance (fMRI) scans of human, monkey, and rat brains show the activation of neurons in the brain area that correspond to brain areas likely active in the mind of another human (or monkey, rat) being observed.
Giacomo Rizzolati and his colleagues at the University of Parma discovered this activity in the brain of a macaque monkey who was observing another macaque grasping for a piece of fruit.
The neurons activated in the observing monkey are in the same area as in the observing monkey when itself reaches for a piece of fruit, thus assumed to "mirror" the thought processes of the observed monkey. In humans, philosophers of mind describe the observer as having a "theory of mind" about the observed person. The correlation between mirror neurons is said to explain human empathy.
However, there is no obvious causal connection between the two minds, let alone between the specific brain areas. So it is likely that the correlated mirror neuron firings are being caused independently by two similar causes.
In our
Experience Recorder and Reproducer model of the mind, neurons that have been wired together by earlier experiences will fire together when presented with a new experience that is similar in some way.
The ERR model postulates that
thought consists of past experiences that resemble the content of current thoughts, providing
alternative possibilities for new thoughts and actions. Similar related past experiences, perhaps with different outcomes, can provide the
context needed for decisions about what to do next.
Being "aware" of those past related experiences, including our past feelings, is the essence of consciousness. This is a version of
William James' "stream of consciousness" and the
"two-stage model" of free will.
As
Nancy Kanwisher and her colleague Rebecca Saxe at MIT have shown, "a region at the junction of the temporal and parietal lobes of the right hemisphere is selectively engaged when one thinks about what another person is thinking." ("Functional Specificity in the Human Brain,"
PNAS, June 22, 2010, vol.107, no.25, p.11166)
We can understand the mirroring of neurons as caused by the observer
thinking about what the observed person is
doing! But this assumes the observed person is thinking about what s/he is doing, and with humans that is often not the case. And as
Gottlob Frege's
Sinn and Bedeutung argued, two persons may share a concept but differ as to its meaning, because they have had different experiences.
Importantly, what the observed person is
doing includes their facial expressions and bodily motions, which can reveal how the observed person is
feeling. Ever since Charles Darwin's epic 1872 study
The Expression of the Emotions in Man and Animals, it is well known that facial expressions and bodily positions display a range of emotions in humans and animals. He wrote "the young and the old of widely different races, both with man and animals, express the same state of mind by the same movements."
And Darwin thought these expressions are innate (i.e., genetic). He wrote "Whenever the same movements of the features or body express the same emotions in several distinct races of man, we may infer with much probability, that such expressions are true ones, —that is, are innate or instinctive."
Where
Noam Chomsky's "universal grammar" of human languages may not be innate, observing another's feelings seems to be built-in to all animals, but can be refined in the observer by learned experiences.
Consider the lowly rat. Christian Keysers, a member of Rizzolati's original team at Parma, moved to Groningen in the Netherlands, where he and his team published "Experience Modulates Vicarious Freezing in Rats: A Model for Empathy," (PLoS One. 2011; 6(7): e21855) They wrote "By comparing the reaction of witnesses with or without previous footshock experience, we examine the role of prior experience as a modulator of empathy." They concluded that their research provides "a paradigm to study empathy as a social loop."
Now our Experience Recorder and Reproducer model of the mind shows how information about feelings (sometimes called "qualia") can "come to mind" without the "central" or "parallel distributed" processing of "computational" neuroscience. When a particular experience fires a network of neurons,
Donald Hebb argued that these neurons get "wired together." Our ERR model expands the Hebbian hypothesis to include the idea that when a future experience resembles the original in some way, those neurons "wired together" will again fire together,
reproducing that original experience, even several related experiences may come to mind, providing context for decisions on what to think/say/do next.
The survival value of recalling related past experiences is obvious. Critically important is the recall of any emotions felt in the original experiences. If the wired together neurons include connections to basil ganglia, then the amygdala and hippocampus nuclei will re-produce the original pleasure or pain. As William James argued, all these experiences may produce a "blooming, buzzing, confusion." But knowledge of the consequences of past similar situations, and focusing on or giving attention to the one with the most positive outcome, provides the Jamesian model for making free choices that are morally responsible, consistent with the agent's beliefs, motives, and desires.