Online research in philosophy

1. Properties of mirror neurons in monkeys. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 000 1.1. Action types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 000 1.2. Context effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 000 2. Is there a human ‘mirror neuron system’? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 000 2.1. Monkeys versus humans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 000 2.2. Action understanding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 000 3. The development of mirroring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 000 3.1. Imitation in newborns? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 000 3.2. Effects of experience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 000 3.3. Effects of sensorimotor experience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

We focus on the evolution of action capabilities which set the stage for language, rather than analyzing how further brain evolution built on these capabilities to yield a language-ready brain. Our framework is given by the Mirror System Hypothesis, which charts a progression from a monkey-like mirror neuron system (MNS) to a chimpanzee-like mirror system that supports simple imitation and thence to a human-like mirror system that supports complex imitation and language. We present the MNS2 model, a new model of action recognition learning by mirror neurons of the macaque brain and augmented competitive queuing, a model of opportunistic scheduling of action sequences as background for analysis of modeling strategies for simple imitation as seen in the great apes and complex/goal-directed imitation as seen in humans. Implications for the study of language are briefly noted.

Both macaque monkeys and humans have been shown to have what are called ‘mirror neurons’, a class of neurons that respond to goal-related motor-actions, both when these actions are performed by the subject and when they are performed by another individual observed by the subject. Gallese and Goldman (1998) contend that mirror neurons may be seen as ‘a part of, or a precursor to, a more general mind- reading ability’, and that of the two competing theories of mind-reading, mirror neurons lend support to simulation theory. I here offer four reasons why I think mirror neurons do not provide support for simulation theory over its contender, theory theory.

In a New York Times article last month, entitled Cells that read minds, the neuroscience reporter, Sandra Blakeslee (January 10, 2006) provided a list of all the things that mirror neurons can explain. As we know, mirror neurons, discovered by Rizzolattis group in Parma, are neurons that are activated when we engage in action, and when we perceive intentional movement in another person. According to Blakeslee and the scientists she interviewed, mirror neurons explain not only how we are capable of understanding another persons actions, but also language, empathy, how children learn, why people respond to certain types of sports, dance, music and art, why watching media violence may be harmful and why many men like pornography. Let me set aside the controversial questions about whether mirror neurons can explain all of these things, and accept that mirror neurons are clearly smart little cells. But let me ask whether Blakeslee and her scientists are expressing things in the right way.

Mirror neurons are neurons which fire in two distinct conditions: (i) when an agent performs a specific action, like a precision grasp of an object using fingers, and (ii) when an agent observes that action performed by another. Some theorists have suggested that the existence of such neurons may lend support to the simulation approach to mindreading (e.g. Gallese and Goldman, 1998, 'Mirror neurons and the simulation theory of mind reading'). In this note I critically examine this suggestion, in both its original and a revised form (due to Iacoboni et al., 2005, 'Grasping the intentions of others with one's own mirror neuron system'), and argue that the existence of mirror neurons can in fact tell us very little about how intentional attribution actually proceeds.

Selected contributions to the symposium on "Mirror neurons and the evolution of brain and language" held on July 5-8, 2000 in Delmenhorst, Germany.

Commonsense says we are isolated. After all, our bodies are physically separate. But Seneca’s colamus humanitatem, and John Donne’s observation that “no man is an island” suggests we are neither entirely isolated nor separate. A recent discovery in neuroscience—that of mirror neurons—argues that the brain and the mind is neither built nor functions remote from what happens in other individuals. What are mirror neurons? They are brain cells that process both what happens to or is done by an individual, and, as it were, its perceived “refl ection,” when that same thing happens or is done by another individual. Thus, mirror neurons are both activated when an individual does a particular action, and when that individual perceives that same action done by another. The discovery of mirror neurons suggests we need to radically revise our notions of human nature since they offer a means by which we may not be so separated as we think. Humans unlike other apes are adapted to mirror interact nonverbally when together. Notably, our faces have been evolved to display agile and nimble movements. While this is usually explained as enabling nonverbal communication, a better description would be nonverbal commune based upon mirror neurons. I argue we cherish humanity, colamus humanitatem, because mirror neurons and our adapted mirror interpersonal interface blur the physical boundaries that separate us.

The neurological discovery of mirror neurons is of eminent importance for the phenomenological theory of intersubjectivity. G. Rizzolatti and V. Gallese found in experiments with primates that a set of neurons in the premotor cortex represents the visually registered movements of another animal. The activity of these mirror neurons presents exactly the same pattern of activity as appears in the movement of one's own body. These findings may be extended to other cognitive and emotive functions in humans. I show how these neurological findings might be “translated” phenomenologically into our own experienced sensations, feelings and volitions.

We believe that an account of the role of mirror neurons in language evolution should involve a greater emphasis on the auditory properties of these neurons. Mirror neurons in premotor cortex which respond to the visual and auditory consequences of actions allow for a modality-independent and agent-independent coding of actions, which may have been important for the emergence of language.

The discovery of mirror neurons has been hailed as one of the most exciting developments in neuroscience in the past few decades. These neurons discharge in response to the observation of others’ actions. But how are we to understand the function of these neurons? In this paper I defend the idea that mirror neurons are best conceived as components of a sensory system that has the function to perceive action. In short, mirror neurons are part of a hitherto unrecognized “sixth sense”. In this spirit, research should move toward developing a psychophysics of mirror neurons.