Self-absorbed rock star stereotype aside, it would be difficult to determine causality if this were the case. Do more empathetic people choose to take up music (à la the tortured artist), or does musical training make one more empathetic?
The best way to address question #1 is to look at those undergoing musical training. One such study reported that a 9 month-long program of musical group interaction (MGI) increased emotional empathy in 8-11 year old children (Rabinowitch et al., 2012). The MGI program consisted of musical "games" that seemed [to me, at least] designed to increase empathy, rather than musical prowess: entrainmentgames to be as rhythmically coordinated as possible,imitation games to repeat the musical phrases or gestures of the previous participant, and other games that called on the constructs of shared intentionalityand intersubjectivity.
Along with a passive control group that received no training, an active control group engaged in a verbal storytelling and drama version of group interaction that didn't involve music, singing, or gesture. It's notable that 33% of all children did not play a musical instrument (which included singing), so the study didn't really ask whether musical training per se can make you more empathetic. Nonetheless, there was ap=.054 level interaction of time (pre- vs. post-training) and group (MGI vs. both controls, who did not differ) on the self-report measure of empathy[which might have resulted from a higher pre-training empathy in controls, along with less improvement].
However, the MGI and control groups improved to an equivalent extent on an emotional face matching task, also designed to measure emotional empathy. While it's probably beneficial for children to engage in these group activities, we do not yet have a positive answer to question #1.
Do Musicians Show More Mirror Neuron Activity?
This question has a trivial element to it: of course a trained violinist will have a greater understanding of the movements and sounds involved in Beethoven's Violin Concerto in D major, so you'd expect differences in brain activity somewhere to reflect this.
There are at least two studies potentially relevant toquestion #2 (Chapin et al., 2010; Babiloni et al., 2012). In neither case, however, do we need to invoke the existence of the mirror neuron system.
In the first, BOLD signal changes in response to two different versions of the same musical piece (Chopin's Etude in E major) were compared in an fMRI study (Chapin et al., 2010). One version was an expressive piano performance with dynamic stimulus fluctuations, and the other was a synthesized "mechanical" version. In addition, the participants had varying levels of musical training: 7 were experienced (mean 9.2 yrs training) and 7 inexperienced (0.7 yrs training), with 7 more thrown out for various reasons. These are very small groups by modern fMRI standards.3
Participants rated their emotional arousal and emotional valence while listening to the pieces before and after scanning, but not during the fMRI experiment. The combined arousal and valence ratings were not consistently correlated across the two time points, so making inferences about what the participants were feeling during the experiment is dicey.
The fMRI results showed different activation patterns according to the main effects of performance type and musical experience (shown below). Mirror neuron-ish areas (inferior parietal lobule, inferior frontal gyrus but too anterior) showed greater activation for the expressive piece in both groups (A), but these regions didn't differ as a function of musical experience (B).
Fig. 4 (Chapin et al., 2010). fMRI ANOVA results.Brain activations (F-maps) showing a significant main effect of a) performance type (F (1,24) > 7.19, corrected p < .02), SCG = subcallosal gyrus, PHG = parahippocampal gyrus, vACC = ventral anterior cingulate, FPC = frontopolor cortex, DMPFC = dorsal medial prefrontal cortex; and b) main effect of musical experience, BG = basal ganglia, vStri = ventral striatum.
But there was an interaction between performance type and musical training, with experienced participants showing greater activation for the expressive piece in the too-anterior-for-mirror neurons IFG and the inferior parietal lobe. Importantly, activation in the mirror neuron-ish areas related to tempo changes in the expressive piece did not differ according to musical training:
An unexpected finding of this study was that, for all participants, the tempo fluctuations of the expressive performance correlated with dynamic activation changes in brain regions that are consistent with the human mirror neuron system, including bilateral BA 44/45, superior temporal sulcus, ventral PMC, and inferior parietal cortex, along with other motor-related areas and with insula.
Thus, the ability to perform a piece of music did not make a difference in the mirror neuron system BOLD response, so we do not have a positive answer to question #2. 4
Do Emotionally Empathetic Musicians Show More Mirror Neuron Activity?
Finally, the study of Babiloni et al. (2012) actually asked a third question: do trained musicians with more emotional empathy show greater mirror neuron system activity while watching their own performance, compared to musicians with a lower emotional empathy score?
The participants were the members of three internationally renowned saxophone quartets (n=12) who played a classical music piece by Domenico Scarlatti while their EEG activity was recorded. They also watched a video of their own ensemble performance while EEG was recorded.
Fig. 1A (Babiloni et al., 2012): Overview of the four musicians playing in ensemble during simultaneous EEG recordings.
The participants completed Baron-Cohen's Empathy Quotient Test (EQT) to assess emotional empathy ("emotional contagion" - the ability to mirror an emotional response observed in another person and to experience it vicariously) and cognitive empathy (perspective-taking or theory of mind). Skipping over all the technical details to the bottom line, emotional empathy scores correlated with the degree of alpha wave desynchronization over a "mirror neuron" area in the right inferior frontal cortex during observation of their own performance:
Results showed that the higher the empathy quotient test score, the higher the alpha desynchronization in right BA 44/45 during the OBSERVATION referenced to RESTING condition. Empathy trait score and alpha desynchronization were not correlated in other control areas or in EXECUTION/CONTROL conditions. These results suggest that alpha rhythms in BA 44/45 reflect “emotional” empathy in musicians observing own performance.
Finally, we have a winner! The answer to question #3is yes. Granting all the authors' assumptions and disregarding the relatively low n (for now), a higher emotional empathy score was associated with greater cortical activity in a mirror neuron area when a musician observed his own saxophone performance (as indexed by the percentage reduction, or desynchronization, of EEG alpha power).
Did this have anything to do with their proficiency in playing with a musical ensemble? Probably not, but it might have made their music more powerful. Many punk musicians, for instance, were not very proficient, but their music was very emotionally intense and resonated with listeners.
ADDENDUM (Dec 30, 2012): An important condition that was not included in this study is the observation of OTHER sax ensembles. Although watching one's own performance includes self and close colleagues, a true test of empathy would be to watch the performance of OTHERS. Watching a video of yourself involves a distinct memory of playing the piece, as well as emotions related to self-consciousness (e.g., pride, modesty, embarrassment at a minor slip, etc.).5
ADDENDUM #2 (Dec 31, 2012): An anonymous commenter said that the EEG paper is totally bogus due to major unavoidable artifacts and to the uncertainty of EEG source localization. I address these technical problems and limitations in a subsequent comment.
...people should be able to touch one another and feel each other's pain. Physically, like you should be able to touch someone's cheek and feel their toothache; and emotionally, if you move someone, touch them deeply, you have to take responsibility for that depth of feeling and care about them.
Some have suggested that synesthesia for pain is mediated by (wait for it...) mirror neurons! But Hersh actually does have color-music synesthesia. E major is red, for instance. And this: "New song is done. It's burgundy and ochre with a sort of Day-Glo turquoise bridge—another tattoo on this pathetic little body." (ibid, p. 90).
2 The human mirror neuron system extends well beyond the traditional ventral premotor and inferior parietal areas of monkey neurophysiology fame.
3 The scanner is a very noisy environment, and in case you're wondering the authors used a sparse temporal sampling technique to increase the signal and to avoid interaction of the scanner noise with the music.
4 Five of the seven experienced participants were trained pianists. They were unfamiliar with this specific piece, but I'm assuming they have the ability to perform it themselves.
5 This was pointed out to me by Sandra Kiume ofChannel N.
Babiloni, C., Buffo, P., Vecchio, F., Marzano, N., Del Percio, C., Spada, D., Rossi, S., Bruni, I., Rossini, P., & Perani, D. (2012). Brains “in concert”: Frontal oscillatory alpha rhythms and empathy in professional musicians NeuroImage, 60 (1), 105-116 DOI:10.1016/j.neuroimage.2011.12.008
Chapin, H., Jantzen, K., Scott Kelso, J., Steinberg, F., & Large, E. (2010). Dynamic Emotional and Neural Responses to Music Depend on Performance Expression and Listener Experience PLoS ONE, 5 (12) DOI: 10.1371/journal.pone.0013812