Re: Mirror neurons at autopsy (Was: [TCS] What is empathy)

On 16 Dec 2012, at 22:59, Elliot Temple <[email protected]> wrote:

> On Dec 16, 2012, at 2:14 PM, David Deutsch <david.deutsch-LR/[email protected]> wrote:
> 
[...]

>> I have no idea whether mirror neurons are physiologically different from other neurons. I see no reason why they should be, and if they are, that can't possibly make them have empathy or anything else. It's programs that have empathy, not hardware, and all universal hardware is equally capable of it (barring marginal issues of speed and memory capacity, which can't be relevant to the issue of what empathy is).
> 
> if it's not physiologically different, why call it a type of neuron?

I don't know the history but I guess it happened is this. Unlike every previous experiment that located particular computations happening in the brain, the experiments that discovered mirror neurons were done with individual neurons (in monkeys, I think). Initially, they were defined as neurons that fire both when an animal does a particular type of behaviour and when it observes (sees or hears) it.

The prevailing explanation for the presence of neurons that behave like this is that they are part of a system that computes, from observing a behaviour of a particular type, how to perform it. For example, how to emit a particular sound, having heard it, or make a particular sequence of arm gestures, having seen it. The function that it computes in a particular species is coded for genetically: apes can imitate one class of behaviours, parrots another, and most species can imitate none. So this explanation predicts that such species have no mirror neurons.

The system that computes the above-mentioned function was then called the mirror *neuron* system. Ideally it should not have had 'neuron' in the name, because one could add that qualifier to every computational system in the brain, so it adds no content. It should have been  called something like the 'mirror system' or the 'imitation system' or the 'sensorimotor translation system'. And I guess it would have been, if its existence had been seriously thought about before the discovery of mirror neurons. As it should have been, on philosophical grounds -- but apparently wasn't.

If the face-recognition system had been discovered in this way, it might now be called the 'face-recognition-neuron system' and some people might then be confused and marvel at what amazing functionality there must be inside a face-recognition neuron to give it the ability to recognise faces. And other people, realising that such functionality would be impossible, and thinking that the whole 'face-recognition-neuron' theory *consists* of claiming that there are such neurons, would deny that the whole 'face-recognition-neuron theory' is true. Both those kinds of people would be mistaken.

[...]

>> What does a "mirror neuron believer" believe?


> A mirror neuron believer disagrees with what Alan explained in his last post in the empathy thread. e.g. by believing they are a reasonable, useful idea instead of bad philosophy and explanationless science.

What does 'they' refer to in that sentence? Is it neurons with a different internal functionality from other neurons, or neurons involved in computing the particular function described above?

-- David Deutsch