It should be noted that many left-handers claim that traditional stringed instruments do not discriminate against left-handers at all, because the left hand (which performs the fingering, chords, etc) actually has the more difficult job, requiring most the dexterity. A 2011 German study of pianists yielded the rather surprising result that, in both right-handed and left-handed players, it was the right hand (which generally plays the melody) that showed a higher degree of motor control. Interestingly, the French Horn is one of the ferw instruments designed to be played with the left-hand, although this does not appear to disadvantage right-handed players.
A survey of 17 professional orchestras in Britain reported that 13% of the musicians were left-handed, slightly, but not hugely, above the national average. Violins in orchestras are always played right-handed, regardless of the handedness of the player, partly to avoid physical clashes in the restricted space of the orchestra’s seating plan and partly for aesthetics, and left-handers playing at a professional level in orchestras do not seem to suffer any particular disadvantage. The same German study mentioned above also indicated that left-handed players of musical instruments do not feel that they suffer from any physical discomfort as a result of the handedness, nor do they experience any negative feelings about playing their instrument.
But the dichotomy between left and right may not actually be the most useful measure of handedness where music is concerned. Back in the 1980s, Stephen Christman pioneered an alternative approach and decided to look at strong-handedness (consistent use of one hand, whether left of right, for all tasks) and weak- or mixed-handedness (scores of 5-5, 6-4, 7-3, 8-2 and 9-1 on a handedness survey like the Edinburgh Handedness Inventory - see the section on Measuring Handedness for more details). Interestingly, he found that the split between strong- and weak-handers is actually about 50-50 (about 2-3% are strong left-handers, and about 47% strong right-handers, with the remaining 50% being varying degrees of mixed-handers). With this in mind, Christman looked at the strength of handedness of different musicians.
As he predicted, Christman found that strong-handed musicians, whether strongly right-handed or strongly left-handed, were significantly more likely to play instruments like horns (where one hand plays most of the complicated action) or piano and percussion (where the two hands tend to follow independent lines of music, and often different rhythms). Mixed-handers, on the other hand, were more likely to excel at stringed or woodwind instruments, where integration and hand coordination is more important. In some ways, then, strong left-handers resemble strong right-handers more than they do mixed-handers.
Many great composers and musicians are claimed to have been left-handed, but the evidence for such claims is often either suspect or, usually, missing completely. Star candidate Ludwig van Beethoven was in fact right-handed, and it is difficult to know where assertions of his left-handedness originated. Likewise with Wolfgang Amadeus Mozart. Violin virtuoso Niccolò Paganini was also right-handed to the best of our knowledge, but he often appears on lists of left-handers, presumably by virtue of his occasional use of an unorthodox technique known as "left-hand pizzicato".
C.P.E Bach’s status as a left-hander appears to rest solely on the evidence of his transcription of a keyboard piece for left-hand solo (probably for a specific client). Similarly, Serge Prokofiev’s claimed left-handedness arises from having written a Concerto for the Left Hand (which was commissioned by the one-armed pianist Paul Wittgenstein), as also did Maurice Ravel. Sergei Rachmaninoff had very large hands and wrote very challenging left-hand parts for the piano, but that does not alter the fact that he was most definitely right-handed.
In the same way, it is often claimed that a disproportionate number of talented singer-songwriters are left-handed, and the names of Paul McCartney, Paul Simon, Jimi Hendrix, Bob Dylan, Cole Porter, Sting, David Bowie, Phil Collins, Robert Plant, Kurt Cobain and others are duly trotted out as “proof” (even though some of these, like Bob Dylan, Sting and Robert Plant, actually turn out to be right-handed, and even left-handed poster boy Jimi Hendrix certainly wrote and ate with his right-hand). The scientific justification of such claims (where such is offered) is usually based on the idea that words are typically processed in the left hemisphere of the brain and melodies and harmonies in the right, and so left-handers are claimed to have an advantage in the superior interhemispheral communication built into the organization of their brains. This is a gross simplification at best, as we have seen in the section on Handedness and the Brain, and can only charitably be described as pseudo-science.
Another possibility not addressed is that this is perhaps not an unexpected number of great singer-songwriters, given the large number of performers in the world of popular music. But the question also remains as to whether this is not just rather too glib and convenient an explanation in the first place, especially when one considers that the left-handed advantage attributed to many sportsmen is that the important brain processes are located near each other in the same hemisphere - essentially the diametrically opposite argument from that used for singer-songwriters!